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Departments of
* Dermatology and
Plastic Surgery, University of Innsbruck, Innsbruck, Austria;
Department of Dermatology, University of Erlangen-Nürnberg, Erlangen, Germany;
British Biotechnology, Oxford, United Kingdom; and
¶ Department of Medicine, Barnes-Jewish Hospital and Washington University School of Medicine, St. Louis, MO 63110
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Abstract |
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 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
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Introduction |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Dendritic cell migration is regulated in a complex manner. Clearly,
inflammatory cytokines such as TNF-
and IL-1
are critical
initiation cytokines (8, 9, 10, 11). Mechanistically, TNF-
down-regulates E-cadherin on epidermal Langerhans cells
(12), thereby loosening these cells within the epidermis
and rendering them responsive to chemotactic stimuli. Such stimuli were
first found to be made by fibroblasts (13).
Recently, chemokines were defined as potent chemoattractants for
cutaneous dendritic cells: macrophage inflammatory protein-3/CCL19
(14) and secondary lymphoid tissue chemokine/CCL21
(15) were shown to enhance the emigration of Langerhans
cells and dermal dendritic cells from the skin.
On their way from the epidermis, Langerhans cells have to cross the
basement membrane and move through connective tissue until they reach a
lymph vessel, which they enter to travel further to the draining lymph
node. The pathway through the collagenous connective tissue is the same
for dermal dendritic cells. Interaction with the extracellular matrix
is therefore important (16). 6
integrins (17) and CD44 (18) were shown to be
critically involved in the migration of dendritic cells from the skin.
Proteinases are probably also relevant, particularly when dendritic
cells have to pass such relatively solid obstacles such as basement
membranes. Matrix metalloproteinases
(MMPs)3 constitute a
family of proteinases (including collagenases) that participate in cell
migration (19). MMPs may be expressed on the surface of
cells, thus allowing for precise, localized proteolysis (20, 21). This would create a path (22) for migrating
cells.
Indeed, MMP-9 could be detected in epidermal Langerhans cells by both
immunohistochemistry (23) and enzymographic assays
(24) that suggested the presence of a functional enzyme.
Inflammatory cytokines (TNF-, IL-1) induce the expression of MMPs
in human macrophages (25). Epicutaneous application of
contact sensitizers that, in turn, induce inflammatory cytokines
(8, 26) also led to the production of MMP-9 by epidermal
Langerhans cells (24). Ab-blocking experiments showed that
Langerhans cell-associated MMP-9 was functional (27). On
the other hand, it was recently observed that the generation of contact
hypersensitivity in MMP-9-deficient mice was not impaired
(28). Since contact hypersensitivity responses reflect a
net effect of different events (migration out of skin, migration
through lymphatics, entry into lymph nodes, finding and activation of
Ag-specific T cells, migration of effector T cells back to the skin),
we decided to study in more detail the role of MMPs in the migration of
dendritic cells directly and exclusively in the skin. We chose an
established skin explant culture model (4, 29, 30).
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Materials and Methods |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Mice of inbred strains C57BL/6 and BALB/c were purchased from Charles River Breeding Laboratories (Sulzfeld, Germany) and used at 8–12 wk of age. Gelatinase B/MMP-9-deficient mice were generated by targeted mutagenesis and maintained on a strain 129/SvEv background (31).
Media and reagents
The culture medium was RPMI 1640 supplemented with 10% FCS,
gentamicin (all from Biological Industries, Kibbutz Beit Haemek,
Israel) and 2-ME (Sigma-Aldrich, St. Louis, MO). The following mAbs
were used for immunohistochemistry of mouse skin:
anti-I-Ab,d (clone B21-2/TIB229, rat IgG2b
from R. M. Steinman, The Rockefeller University, New York,
NY), anti-I-Ad (clone MK-D6/HB3, mouse IgG2a;
American Type Culture Collection, Manassas, VA),
anti-I-Adiverse (clone 2G9, fluoresceinated;
BD PharMingen, San Diego, CA), anti-mature DC (clone 2A1, rat IgG2a
from R. M. Steinman (32, 33)), and anti-CD86/B7-2
(clone GL1, rat IgG2a; BD PharMingen). For human material mAbs
anti-HLA-DR (clone L243/HB55, mouse IgG2a; American Type Culture
Collection), anti-CD1a (clone OKT-6; American Type Culture
Collection), and anti-Birbeck granules (clone Lag, mouse IgG1,
provided by Dr. K. Yoneda, Kyoto University, Kyoto, Japan)
(34) were used. Abs were visualized by immunofluorescence
using biotinylated anti-rat or anti-mouse Igs and
streptavidin-Texas Red (both from Amersham, Amersham, U.K.), as
previously described (5). mAbs specific for MMP-2 (clone
42-5D11, mouse IgG1) and MMP-9 (56-2A4, mouse IgG1) were purchased from
Chemicon International (Temecula, CA). A neutralizing anti-MMP-9
mAb (clone 6-6B, mouse IgG1) and tissue inhibitors of
metalloproteinases (TIMP-1 and -2) were obtained from Oncogene Research
(Cambridge, MA). Neutralizing anti-MMP-2 mAb (clone CA-4001, mouse
IgG1) and another anti-MMP-9 (clone GE-213, mouse IgG1) were
obtained from NeoMarkers (Fremont, CA). Compound BB-3103, a hydroxamic
acid-based, broad spectrum inhibitor of matrix metalloproteinases
(MMPI), was developed by British Biotech Pharmaceuticals (Oxford,
U.K.). The half-maximal inhibitory concentrations, as determined on
purified enzymes, were 2, 20, 30, 20, and 7 nM for MMP-1, -2, -3, -7,
and -9, respectively. In a cell-based assay that measures the shedding
of TNF-, the half-maximal inhibitory concentration was 800 nM, and
complete inhibition was achieved at 5 µM BB-3103.
Skin organ culture
Ear skin from mice was split in dorsal and ventral halves, and the dorsal (i.e., cartilage-free) halves were cultured in 24-well tissue culture plates (one ear per well) as previously described (5, 29). In most experiments, skin was cultured continuously for 48 h. At least six explants (i.e., six wells) were pooled for each experimental condition. Human skin organ cultures were based on recently described methods (29, 35, 36). Standardized pieces of skin were prepared by means of an 8-mm punch from split-thickness skin (0.3 mm). These explants were floated on 1.5 ml culture medium in 24-well plates (one explant per well) for 72 h at 37°C. Cells that had emigrated into the culture medium during this time were harvested, counted, and further evaluated phenotypically. In some experiments (murine and human), epidermis and dermis were separated from each other by incubation of explants in dispase (1 U/ml; Roche, Mannheim, Germany) (37) before the onset of culture; i.e., epidermis and dermis were cultured separately and in parallel.
Preparation of epidermal cell suspensions
Preparation of epidermal cell suspensions was performed by standard trypsinization of epidermal tissue as previously described (29, 38). Cell suspensions were cultured in culture medium supplemented with 500 U/ml recombinant murine GM-CSF. On day 3 of culture, the percentage of Langerhans cells was determined in the hemocytometer. At this point mature Langerhans cells can be readily recognized by their pronounced veiled or hairy shape that clearly sets them apart from the other cells in the suspension (mainly keratinocytes).
Determination of T cell stimulatory capacity
The oxidative mitogenesis assay and the allogeneic MLR were used for this purpose as previously described (39). Resting T cells from spleen and lymph nodes were purified by means of nylon wool columns, followed by a discontinuous Percoll gradient as described previously (40). Varying numbers of Langerhans cells were cocultured with 3 x 105 purified T cells that were either periodated (for the oxidative mitogenesis) or left untreated (for the MLR). After 24 h (oxidative mitogenesis) or 72 h (MLR) tritiated thymidine was added for another 6–18 h. Incorporated radioactivity was determined in a liquid scintillation counter.
Preparation of epidermal and dermal sheets for immunohistochemistry
Skin was floated dermal side down on 0.5 M ammonium thiocyanate for 20–30 min at 37°C. The epidermis was peeled off the dermis, and both parts were cut into 5 x 5-mm pieces and fixed in acetone for 20 min at ambient temperature. Sheets were immunostained as previously described (5).
Intradermal administration of reagents
Cytokines and the MMPI were diluted in PBS/10% FCS and injected with 1-ml tuberculin syringes equipped with a 30-gauge needle. Mice received 30 µl cytokine dilution intradermally into the pinna of one ear and the carrier protein alone into the contralateral ear. After different time points epidermal sheets were prepared, and immunohistochemistry was performed as previously described (5)
Evaluation
The main read-out was the number of dendritic cells that had emigrated from the skin into the culture medium in the course of the 48-h culture. Dendritic cells could be readily identified by their hairy and veiled appearance under the hemocytometer. The mean ± SD are given; Student’s t test for paired samples was applied to test for the significance of differences. The phenotype of emigrated dendritic cells was determined by staining cytocentrifuge smears or flow cytometry. In addition, epidermal and dermal sheets were prepared by means of ammonium thiocyanate (41) and stained with mAbs against MHC class II to identify Langerhans cells in the epidermis and dermal dendritic cells. The density of Langerhans cells in epidermal sheets was counted under the microscope using x40 objective lenses and a calibrated grid. Areas to be counted were selected for interfollicular regions of even staining and regular distribution of positive cells. There, 16–50 grids were randomly chosen. Fields containing hair follicles were excluded from the analyses. Langerhans cells were counted, and basic statistical parameters (means and SD) were calculated.
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Results |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Dendritic cells emigrate spontaneously from murine whole skin
explants into the culture medium over a period of 1–3 days
(6, 42). Between 5,000 and 20,000 dendritic
cells can be retrieved from one dorsal ear half after 48 h. When
compound BB-3101, an MMPI, was added to the cultures, a dose-dependent
reduction in the number of dendritic cells retrieved from the culture
medium was observed (Fig. 1
). Vehicle
controls (DMSO) had no effect on migration (Fig. 1). To rule out a
cytotoxic effect of the MMPI, skin explants from cultures that had
received the highest concentration of MMPI (50 µM) from days 0 to 3
were transferred to fresh, MMPI-free culture medium and cultured for
another 1–3 days. During this period many dendritic cells emigrated
from these explants (Table I). By phase
contrast and in the hemocytometer, MMPI-treated dendritic cells looked
normal and viable (as assessed by trypan blue exclusion). They also had
the hairy morphology typical of fully mature skin dendritic cells.
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). This has been described previously
(5, 6, 11). The presence of an MMPI during the culture
period attenuated the decline in Langerhans cells; more Langerhans
cells stayed behind in the epidermis after 48 h of culture (Fig. 2). However, even at the highest dose of MMPI we did not observe a
complete block of Langerhans cell emigration. Langerhans cells appeared
activated, as defined by their increased MHC class II expression
and their enlarged size. Some specimens were embedded for conventional
transmission electron microscopy. The light microscopic analysis on
semithin sections of long stretches of basement membrane zone revealed
clearly more basal Langerhans cells (i.e., branched cells with clear
cytoplasm) in MMPI-treated cultures compared with untreated cultures
(not shown). Immunohistochemical inspection of the dermis revealed the
typical cords, i.e., lymphatic vessels filled with strongly MHC class
II-expressing, migrating dendritic cells (5). The cords
were present, but reduced in number, and they contained fewer dendritic
cells in MMPI-treated cultures, indicating that fewer dendritic cells
were mobilized when the action of MMPs was inhibited.
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To obtain reproducible and reliable cell counts, it was necessary to standardize the human skin explant cultures as much as possible. This was achieved by using only skin that had been dermatomed with a thickness of 0.2–0.3 mm and by culturing 8-mm punches (0.5 cm2). It was important to culture each explant in a separate 24-well plate. For reasons not further explored, cultures in petri dishes yielded inconsistent results. This is exactly as we had previously described for murine skin explants (42).
When 72-h cultures of human skin explants were treated with graded
doses of the MMPI (compound BB-3103), we observed the same
dose-dependent inhibition of dendritic cell emigration as in the mouse
(Fig. 3). At the highest concentration of
MMPI, emigration was almost abrogated; compared with untreated
cultures, fewer than 5% dendritic cells could be retrieved from the
culture medium. Vehicle controls (DMSO) had no effect on migration
(data not shown). Transfer of MMPI-treated explants onto fresh
MMPI-free culture medium and further culture for 1–2 days
yielded high numbers of emigrant dendritic cells, strongly suggesting
that the MMPI was not toxic and apparently acted in a reversible manner
(Table I
). Lack of toxicity at concentrations of BB-3103 up to 100 µM
was recently also shown for human keratinocytes in vitro
(43).
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, d–f). A broad spectrum inhibitor of MMPs inhibits emigration of dendritic cells from both epidermis and dermis
Dendritic cells that emigrate into the culture medium from whole
skin explants consist of both epidermal dendritic cells (Langerhans
cells) and dermal dendritic cells. The ratio of these two types of
dendritic cells is unknown in the mouse, since there is no commercially
available reliable marker that would distinguish dendritic cells of
epidermal vs dermal derivation; the mAb Lag does not cross-react with
mouse Birbeck granules. In human explant cultures the majority of
emigrated dendritic cells were Langerhans cells, as defined by their
expression of the Birbeck-granule-associated Lag Ag (data not shown).
Due to these uncertainties we decided to separate epidermis from dermis
before the start of the culture and to assess the effects of MMPI on
the two compartments separately. In murine and human cultures we found
an effect on both epidermis and dermis. Although generally fewer
dendritic cells emigrated from dermal sheets than from the
corresponding epidermal sheets, we noted a similar degree of inhibition
in both compartments (Fig. 4). The
inhibitory effect also became obvious when comparing absolute numbers
of emigrated cells in individual experiments (Table II).
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Intradermal injection of an inflammatory cytokine such as TNF-
leads to the emigration of a substantial number of Langerhans cells
from the epidermis (44). In three separate experiments the
TNF--induced decrease in Langerhans cell density, as assessed by
counting Langerhans cells in immunohistochemically labeled epidermal
sheets, was between 15 and 30%. When the broad spectrum MMPI BB-3103
(100 µM in a total injection volume of 30 µl) was coadministered
with TNF- (40 ng in the same total injection volume of 30 µl),
Langerhans cell migration was totally blocked; the density of
Langerhans cells even increased for reasons not further pursued (Table III). MHC class II expression on
Langerhans cells in the epidermis of TNF/MMPI-treated ears was
increased, indicating that these cells were activated by the
inflammatory cytokine, yet paralyzed due to the blocked MMP function
(Fig. 5).
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These experiments were performed with human skin explant cultures.
Narrow band inhibitors of MMP with exclusive specificity for certain
MMPs are not available. Therefore, we chose to test the natural
inhibitors of MMPs, the TIMPs. TIMP-1 and TIMP-2 have some specificity
for MMP-9 and MMP-2, respectively. When added to whole skin explant
cultures (at concentrations ranging from 12.5–200 ng/ml), a strong
inhibition became evident with either TIMP (Fig. 6). Both TIMPs inhibited to a similar
degree at the highest concentration of 200 ng/ml. The numbers of
dendritic cells that could be retrieved from TIMP-treated cultures were
about a quarter of those from untreated control cultures. Similar
observations were made using neutralizing mAbs against MMP-2 (clones
45-5D11 and CA-4001) as well as MMP-9 (clone 6-6B). When whole skin
explants were cultured in the presence of either Ab, the numbers of
dendritic cells that could be retrieved from the culture medium dropped
by 
30–50% (Table IV). The inhibitory
effect was dose dependent. When Abs against MMP-2 and MMP-9 were
combined, the inhibitory effect was more pronounced, indicating an
additive mode of action (Table V).
Dendritic cell emigration from both cultured epidermal sheets and, to a
lesser degree, cultured dermal sheets was also inhibited by the Abs
(Table IV).
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Initially, the density of Langerhans cells in untreated epidermis
of MMP-9-deficient mice was determined and found not to be different
from that in control mice (data not shown). Differences in the degree
of emigration of Langerhans cells could therefore not be attributed to
a smaller starting population of Langerhans cells within the epidermis.
Whole skin explant cultures from MMP-9-deficient mice revealed a
striking impairment of emigration of cutaneous dendritic cells. In
three independent experiments, the numbers of dendritic cells that
could be retrieved from the culture medium were 13, 39, and 34%,
respectively, of the numbers recovered from cultures of age- and
sex-matched littermate controls (Fig. 7).
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We attempted to visualize the MMPs in situ in fresh and cultured
skin. This was only performed with human specimens. In epidermal sheets
obtained from fresh skin and from skin that had been cultured for
72 h, we noted the expression of both types of MMPs on MHC class
II-positive cells, i.e., Langerhans cells. Expression was up-regulated
upon culture of skin explants (Fig. 8).
Staining of Langerhans cells in acetone-fixed epidermal sheets does not
allow an unequivocal distinction between surface and intracellular
localization of Ab reactivities. Therefore, this point was tested with
dendritic cells that had "crawled out" from untreated human skin
explants during the 48-h culture period. They were analyzed by flow
cytometry for the expression of MMPs. Both MMP-2 and MMP-9 were
detected on the surface of these cells (Fig. 9). In contrast, neither immature nor
mature human monocyte-derived dendritic cells nor mature human
CD34+ cord blood stem cell-derived dendritic
cells expressed either of the two MMPs on the cell surface.
Intracellular expression of MMPs in the latter cell types was not
investigated.
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Kobayashi et al. (27) noted an effect of purified
MMP-9 on the expression of MHC class II on Langerhans cells, suggesting
a role for MMP-9 in the maturation process. We have addressed this
question in the MMP-9-deficient model. Epidermal cell suspensions were
obtained by trypsinization and were cultured in bulk until day 3
(39). The numbers of mature Langerhans cells that could be
recovered at the end of the culture period were comparable. Their
morphology under phase contrast (veils) and under the hemocytometer
(hairy) was identical. In both the allogeneic mixed leukocyte reaction
and the oxidative mitogenesis assay cultured Langerhans cells from
MMP-9-/- and MMP-9+/+
mice showed equal stimulatory capacity for resting T cells (Fig. 10). Finally, the expression of the 2A1
Ag, a selective maturation marker (32), did not differ
between MMP-9-deficient mice and controls. Moreover, MHC class II was
strongly expressed, and the MHC class II-associated invariant chain
(mAb In1) was largely absent on cultured Langerhans cells of both
MMP-9-deficient mice and controls, as determined in cytospin
preparations (data not shown).
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Discussion |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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Relevance of MMPs for the migration of epidermal Langerhans cells across the basement membrane
When a Langerhans cell leaves the epidermis it must first cross
the basement membrane (7). We found that both MMP-2 and
MMP-9 are essential for Langerhans cells to leave the epidermis. This
was shown 1) by a synthetic broad spectrum inhibitor (BB-3103), 2) by
inhibition experiments using anti-MMP-2 and -MMP-9 mAbs, and 3)
most strikingly by the use of MMP-9-deficient mice. Given the known
substrate specificity of MMP-2 and -9, namely, collagen type IV, this
is not surprising. Despite their similar specificities, experiments
using Abs against both MMPs suggest that the effects of the two MMPs
may not be identical, but, rather, additive. Kobayashi et al.
(27) have recently demonstrated an MMP effect in a murine
contact hypersensitivity model in which the injection of a neutralizing
anti-MMP-9 mAb into the skin prevented the contact
sensitizer-induced emigration of Langerhans cells from the epidermis
and the accumulation of dendritic cells in the regional lymph nodes.
Similarly, in a human skin explant model Lebre et al. (45)
noted that inhibitors of MMPs prevented the emigration of Langerhans
cells from the epidermis in response to the epicutaneous application of
a sensitizer (nickel). The critical role for MMP-9 in the
transmigration through basement membranes has previously been shown for
other cell types, e.g., T cells (46). It appears not to be
an absolute necessity for all cell types, though, because granulocytes
can migrate normally in the MMP-9-deficient mice (47).
Interestingly, when the MMP inhibitor was injected into the ear skin
together with TNF-, we noted an increased density of Langerhans
cells 24 h thereafter (Table III). Apparently, the compound had
inhibited egress of Langerhans cells from the epidermis, but not the
influx of Langerhans cell progenitors, leading to some degree of
Langerhans cell accumulation in the epidermis. This may reflect
different MMP-related requirements of emigrating Langerhans cells and
immigrating precursors.
Relevance of MMPs for the migration of Langerhans cells and dermal dendritic cells through the dermal connective tissue
After traversing the basement membrane, migrating dendritic cells need to work their way through the dermal meshwork of collagen and elastin fibers until they finally enter lymphatic vessels (7). Clearly, MMPs are involved in dendritic cell migration through the dermis. This can be concluded from the marked inhibition of emigration from dermal explant cultures by a broad spectrum inhibitory compound and by mAbs against MMP-2 and MMP-9. Thus, dendritic cells use MMP-2 and -9 for "creating their path" (22) through the dermal extracellular matrix.
Relevance of MMPs in the contact hypersensitivity model
These data also bear on the recent observations that the development of contact hypersensitivity is not impaired in MMP-9-deficient mice (28). In light of the dramatic inhibition of Langerhans cell migration in these gene-deficient mice, three possible, not mutually exclusive, explanations might account for this surprising discrepancy. 1) Perhaps migration of Langerhans cells in response to a contact allergen such as 2,4-dinitro-1-fluorobenzene, which was used in the above-mentioned study, is not inhibited in MMP-9-deficient mice, as opposed to the data shown here in the skin explant model. This is unlikely, however, since the mechanisms of migration appear to be the same in contact hypersensitivity and explant cultures (5, 10, 11). 2) In addition, contact hypersensitivity might be brought about by the free diffusion of the contact allergen into the lymph nodes where it would bind to (i.e., haptenize) local dendritic cells. It has recently been emphasized that this route of haptenization is important and should not be forgotten (48). Yet, the fact that in MMP-3-deficient mice, where such free diffusion most likely occurs to the same extent as in MMP-9-deficient mice, contact hypersensitivity is suppressed (28) would argue against this explanation. 3) If migration of Langerhans cells is blocked or strongly inhibited, this would imply that dermal dendritic cells are responsible for transport of the hapten to the lymph nodes and thus for sensitization of the mice. We have not directly investigated the migration of dermal dendritic cells in MMP-9-deficient mice. Experiments with dermal explants from normal mice using neutralizing anti-MMP-9 mAbs revealed that dermal dendritic cells are also dependent on MMP-9, albeit not completely. In the presence of the blocking Ab substantial numbers of dendritic cells still emigrated from dermal explants. This may be similar in the MMP-9-/- mouse. Given the extraordinary T cell stimulatory capacity of dendritic cells, these few dermal dendritic cells together with the few Langerhans cells that still migrate in the absence of MMP-9 might successfully induce contact hypersensitivity.
Dendritic cell maturation and MMPs
Maturation and migration of skin dendritic cells are tightly linked processes (5). Migration can apparently not occur without concomitant maturation. Dendritic cells in skin explant cultures have presumably received their initial maturation and migration stimulus by the stress exerted when excising and handling the skin for the culture. Therefore, they migrate spontaneously. This initial stimulus could only partially be neutralized by the MMP inhibitor. Migration, however, was greatly reduced. Experimentally added inflammatory cytokines accelerate migration; anti-inflammatory treatments slow it down (11). Phenotypical features of dendritic cell maturation, however, such as augmented MHC class II expression, translocation of MHC class II from intracellular pools to the surface membrane (49), and enlargement of the cells, were not influenced by the inhibitor. Importantly, in MMP-9-/- mice the expression of maturation markers and the T cell stimulatory capacity of mature, i.e., cultured Langerhans cells were found to be normal. From this it appears that once an initial inflammatory stimulus has been delivered to dendritic cells, the neutralization of MMPs blocks migration, but not phenotypical, morphological, and functional maturation. This may be different when the MMPs are blocked before the initial inflammatory stimulus is given, such as in Kobayashi’s experiments in which an anti-MMP-9 mAb was injected into the skin before a contact sensitizer was applied epicutaneously (27). In that setting maturation, as measured by increased MHC class II expression on Langerhans cells, was indeed inhibited.
Relevance in vivo
Dendritic cells are increasingly used for immunotherapeutic approaches, predominantly in oncology (50). Tumor Ag-charged autologous dendritic cells are administered intracutaneously (s.c. or intradermally). They are expected to migrate to the draining lymph nodes and to induce immunity there. This has been shown to happen, albeit at a low efficiency. A vast majority of dendritic cells remain at the injection site in the skin (51, 52, 53). Ways are being sought to improve the migration rate of these cells. Treatment of dendritic cells with TNF-related activation-induced cytokine has recently been shown to increase the numbers of injected dendritic cells that arrive in the lymph nodes in a mouse model (54). Two aspects of the data presented here may be of relevance to dendritic cell vaccinations into the skin. First, we showed that MMPs are critical for the migration of dendritic cells within the dermal meshwork and not only for penetration of basement membranes. This is the very situation of a vaccination where the injected cells are placed directly into the dermis or subcutis. It is therefore tempting to speculate that the concomitant administration of reagents that activate MMP function might be of benefit in dendritic cell vaccinations (24). Secondly, we found that cutaneous emigrant dendritic cells express MMP-2 and MMP-9 on their surfaces, whereas monocyte-derived dendritic cells do not have cell surface expression of these MMPs, although intracellular MMP-9 and MMP-9 secretion into the culture medium has recently been shown (55). This discrepancy may be biologically relevant. The data emphasize the need to thoroughly investigate and compare the different types of dendritic cells with regard to their migratory behaviors.
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Acknowledgments |
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Footnotes |
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2 Address correspondence and reprint requests to Dr. Nikolaus Romani, Department of Dermatology, University of Innsbruck, Anichstrasse 35, A-6020 Innsbruck, Austria. E-mail address: nikolaus.romani{at}uibk.ac.at
3 Abbreviations used in this paper: MMP, matrix metalloproteinase; MMPI, inhibitor of MMP; TIMP, tissue inhibitor of metalloproteinase.
Received for publication July 5, 2001. Accepted for publication March 4, 2002.
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References |
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TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
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in the initiation of primary immune responses in skin. J. Immunol. 150:3698.[Abstract]
and interleukin-1 for migration. Immunology 92:388.[Medline]
and IL-1. J. Leukocyte Biol. 66:462.[Abstract]
are potent chemoattractants for in vitro- and in vivo-derived dendritic cells. J. Immunol. 162:3859.6 integrins are required for Langerhans cell migration from the epidermis. J. Exp. Med. 186:1725. and promotes tumor invasion and angiogenesis. Genes Dev. 14:163. and IL-1 selectively induce expression of 92-kDa gelatinase by human macrophages. J. Immunol. 157:4159.[Abstract]
. Immunology 81:395.[Medline]
. J. Interferon Cytokine Res. 21:495.[Medline]This article has been cited by other articles:
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S. Darmanin, J. Chen, S. Zhao, H. Cui, R. Shirkoohi, N. Kubo, Y. Kuge, N. Tamaki, K. Nakagawa, J.-i. Hamada, et al. All-trans Retinoic Acid Enhances Murine Dendritic Cell Migration to Draining Lymph Nodes via the Balance of Matrix Metalloproteinases and Their Inhibitor |
) or the presence (
) of graded
concentrations of inhibitor BB-3103. a and
b, Representative experiments; absolute numbers of
dendritic cells emigrated per one skin explant (i.e., one ear half) are
indicated on the y-axis. c, All
experiments (including those shown in a and
b) are summed up. Spontaneous emigration of dendritic
cells in plain culture medium was set equal to 100%. Differences were
highly significant: medium only vs 10 µM BB-3103,
p < 0.0001 (range, 25–49%; n
= 7); medium only vs 50 µM BB-3103, p > 0.0001
(range, 11–46%; n = 9). 
(a),
emigration in the presence of DMSO only. Error bars indicate SDs.
