| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Original Articles |
Institute of Anatomy (G.A., S.K., C.S.), Department of Surgery (M.S.), and Institute of Immunology and Transfusion Medicine (M.K.), University of Leipzig, Leipzig 04103, Germany
Address all correspondence and requests for reprints to: Dr. G. Aust, University of Leipzig, Institute of Anatomy, Liebigstrasse 13, Leipzig, 04103. E-mail: ausg{at}medizin.uni-leipzig.de
Abstract
Stromal-derived factor 1 (SDF-1) and CXCR4 comprise a unique chemokine/chemokine receptor pair, exhibiting important functions in morphogenesis and growth regulation as well as attractant properties on T lymphocytes. No data are available on SDF-1 and CXCR4 in normal or pathological thyroid tissues.
SDF-1, CXCR4, and CD18 messenger ribonucleic acid (mRNA) as a marker of leukocytic infiltration were quantified in tissues affected by thyroid adenoma (n = 11) and Graves’ disease (GD; n = 16) using competitive RT-PCR. SDF-1 mRNA levels differed significantly between autonomous adenomas and the corresponding normal tissue, but not in GD between patients with low or high leukocyte infiltration, thyroid peroxidase, and TSH receptor autoantibodies, respectively. We found a strong correlation between CXCR4 and CD18 mRNA, which indicates CXCR4 expression by leukocytes.
To define the cellular source of SDF-1 and CXCR4 in thyroid tissue, we examined various thyroid-derived cells. Fibroblasts are the most potent producers of SDF-1, although thyrocytes also secrete SDF-1 in vitro. Leukocytes showed very weak SDF-1 mRNA levels and no secretion of the chemokine. Immunohistology confirmed and extended these results; SDF-1 expression was found in fibroblasts, but not or very weakly in CD45+ leukocytes and thyrocytes. Only leukocytes were CXCR4+. As examined by flow cytometry, the number of CD3+ T cells expressing CXCR4 is significantly higher in the thyroid than in peripheral blood.
SDF-1 seems to be involved in thyroid tissue homeostasis in thyroid adenoma, but not in the maintenance of lymphocytic infiltration in GD.
ORIGINALLY IDENTIFIED for its ability to
activate and chemoattract immune cells, the stromal-derived factor 1
(SDF-1) chemokine also fits additional important functions such as
regulatory properties in growth and morphogenesis (1).
SDF-1 and its unique receptor CXCR4 are in many respects different from
other chemokine/chemokine receptor pairs. Human SDF-1
is almost
identical to the murine homologue, differing in one amino acid residue
only. This strong evolutionary conservation of the primary structure of
SDF-1, which is uncommon for a chemokine, and the unique chromosomal
localization on chromosome 10q11 of the SDF-1 gene (2)
gave the first indications that SDF-1 exerts important physiological
functions. Studies with genetic knockouts of both SDF-1 and CXCR4 have
underscored their vital role during cardiogenesis, vasculogenesis, and
leukopoiesis (3, 4). It is noteworthy that the lethal
phenotype caused by the genetic knockouts has not been observed for
other chemokines and chemokine receptors.
The constitutive SDF-1 expression in all tissues, although at different levels, is consistent with the presence of a GC-rich sequence in the 5'-flanking region of the SDF-1 gene, as is often the case with housekeeping genes (2). However, SDF-1 messenger ribonucleic acid (mRNA) was reduced or lost in colonic adenomas and in the majority of gastrointestinal tumors compared with that in normal adjacent tissues (5, 6). Moreover, 27 malignant human cell lines of different origins were SDF-1 mRNA negative (5). There are no other reports on SDF-1 expression in human adenomas and cell lines. SDF-1 and its receptor may be involved in the maintenance of the normal thyroid architecture. In this study we compared the expression of SDF-1 and CXCR4 in thyroid autonomous single adenomas with the corresponding normal, but quiescent, tissue.
Besides the major role of SDF-1 in the maintenance of tissue homeostasis, SDF-1 plays a critical role in lymphocytic circulation and immune surveillance in postnatal life. SDF-1 belongs to the CXC chemokine family. In contrast to the Glu-Leu-Arg (ELR) motif containing CXC chemokines, which are effective on neutrophils, SDF-1 chemoattracts rested T lymphocytes and monocytes, dendritic cells, and CD34+ progenitor cells (7, 8). CXCR4 is found on naive T cells and Th2 cells, monocytes/macrophages, as well as dendritic and endothelial cells (9, 10). Thus, both SDF-1 and CXCR4 may be involved in the maintenance of leukocyte infiltrates in thyroids affected by Graves’ disease (GD). Such thyroids showed a strong accumulation of T cells, monocytes, and B cells, which are responsible for the production of autoantibodies against thyroid peroxidase (TPO) and the TSH receptor (TSH-R) (11, 12). Here, intrathyroidal SDF-1 and CXCR4 mRNA levels were correlated to the 1) levels of TPO and TSH-R antibodies and 2) intrathyroidal leukocyte accumulation.
Apart from the fact that no information is available on the expression of SDF-1 and its receptor in the thyroid under normal and pathological conditions, their cellular sources and regulation are unknown. Thus, thyroid-derived lymphocytes, fibroblasts, and thyrocytes were isolated and, in addition to five thyroid carcinoma cell lines, checked for their basal and stimulated capacity to express SDF-1 and CXCR4 in vitro at the mRNA and protein levels.
Subjects and Methods
Patients
GD and thyroid adenoma (TA) were diagnosed on the basis of
clinical, biochemical, and immunological features as well as from
scintiscans (Table 1
). In all patients
with unifocal TA thyroid scans, Tc99m
pertechnatate showed a single hot nodule and a low uptake in the rest
of the thyroid. Antibodies against the TSH-R [TSH binding-inhibiting
Ig (TBII)] and TPO were measured in serum obtained during the 2 weeks
before operation with commercial RIA kits (Henning, Berlin, Germany).
Thyroid samples were obtained during operation. Fat and connective
tissue were removed immediately. The TA tissue was carefully separated
into adenomatous and normal tissues. In all cases the presence of a
capsule was checked. The samples were frozen and stored in liquid
nitrogen until required. CD18 mRNA was quantified as a degree of
leukocytic infiltration using competitive RT-PCR (see below). The
correlations between SDF-1 and CXCR4 mRNA levels and serum anti-TPO and
TBII levels as well as CD18 mRNA expression were calculated using
Spearman’s method. Differences in CXCR4 and SDF-1 mRNA levels between
GD patients with no or low as well as high anti-TPO levels and in
autonomous and normal tissues of TA patients were analyzed using the
Mann-Whitney U test for unpaired samples.
|
Thyroid-derived cells were prepared from three thyroids of patients with GD. Thyrocytes and lymphocytes were enriched after gradual enzymatic tissue digestion and cultured over a period of 16 h as previously described (12). Thyrocytes were obtained from the adherent fraction by incubating the cell monolayer with PBS in the absence of Ca2+/Mg2+ for 45 min (13). Residual fibroblasts within the thyrocyte fraction were eliminated by incubating the thyrocytes with the fibroblast-specific monoclonal antibody FibAS01 and goat antimouse IgG-Dynabeads M450 (DynAl, Hamburg, Germany) (13). Thyroid-derived lymphocytes were enriched from the nonadherent fraction by Ficoll density gradient centrifugation (14). By culturing small pieces of thyroid tissue in DMEM (Life Technologies, Inc., Grand Island, NY) with 10% FCS, outgrowing fibroblasts were obtained, harvested, and used in the fifth to seventh passage. The purity of the isolated thyroid-derived cells was determined using the indirect immunofluorescence technique on a FACScan (Becton Dickinson and Co., Mountain View, CA) (12, 13). The human C643, SW1736, and HTh74 anaplastic thyroid carcinoma lines were provided by Dr. N.-E. Heldin (University of Uppsala, Uppsala, Sweden). The original dedifferentiated 8505C papillary carcinoma line and the FTC-133 follicular carcinoma line were purchased from the German Collection of Microorganisms and Animal Cell Cultures. All cell lines were cultured in DMEM/10% FCS.
In vitro cultures
Cells (1 x 105/well) were cultured
on 24-well plates for 24 h. The medium was aspirated and replaced
with 500 µL Opti-MEM (Life Technologies, Inc.) without
FCS to eliminate its possible stimulation. The medium contained human
interleukin-1 (IL-1; 10 U/mL; Sigma, Deisenhofen,
Germany), tumor necrosis factor- (TNF; 5 ng/mL;
Sigma), lipopolysaccharide Escherichia coli
055:B5 (100 ng/mL; Sigma), or 10 ng/mL phorbol
12-myristate 13-acetate (PMA; Sigma). For each stimulator,
triplicate cultures were analyzed.
The maximum or plateau of SDF-1 mRNA or protein expression was determined with HTh74 thyroid carcinoma cells taken as a standard. The SDF-1 mRNA level reached a plateau after about 12 h and was then analyzed. The highest SDF-1 protein levels were measured after 48 h. After that, the protein level decreased, probably due to proteolytic degradation (data not shown). For lymphocytes, the SDF-1 mRNA and protein levels were examined after 6 and 12 h, as unstimulated cells died during this time, impeding a measurement of basal quantity any later. Lysis buffer (0.2 mL) from the QIAGEN total RNA isolation kit (Hilden, Germany) was added to each culture well; the contents of three wells were then pooled for each cell type and frozen in liquid nitrogen for further mRNA analysis. The protein levels of cultures obtained from separate experiments were presented as the mean ± SEM. The Mann-Whitney test was used to determine the statistically significant difference between basal and stimulated cells.
SDF-1 enzyme-linked immunosorbent assay (ELISA)
The supernatants from the cultures were removed,
frozen, and assayed for SDF-1 by ELISA. SDF-1 exists in two isoforms.
The SDF1 and SDF1ß proteins diverge only by the presence of four
additional amino acids at the carboxyl-terminal end in the ß-isoform.
Relevant differences between both isoforms concerning the binding
affinity to CXCR4 or different distributions under normal and
pathological conditions are not known. Thus, two ELISA systems, one for
the -isoform and one for the ß-isoform, were performed. Briefly,
ELISA plates were coated with 100 µL/well antihuman SDF-1 capture
antibody (clone 79018.111; all ELISA reagents from R & D Systems, Wiesbaden, Germany) at 2 µg/mL overnight. All
incubation steps were performed at room temperature. After each
incubation step, the solution was aspirated, and the wells were washed
three times with PBS/0.05% Tween 20. The plates were blocked with 300
µL PBS/1% BSA, 5% sucrose, and 0.05% NaN3
for 2 h. One hundred microliters of the undiluted cell culture
supernatant or of the human recombinant SDF-1 or -ß standard were
added and incubated for 2 h. One hundred microliters of the
biotinylated anti-SDF-1 or -ß detection antibody were then
incubated for 2 h. One hundred microliters of
streptavidin-horseradish peroxidase were added to each well and
incubated for 20 min. One hundred microliters of substrate solution
were applied (tetramethylbenzidine) for 20–30 min, and 50 µL stop
solution (1 mol/L H2SO4)
were added. The plates were measured within 30 min using a microreader
set at 450 nm.
RNA isolation and complementary DNA (cDNA) synthesis
Total cellular RNA was isolated from thyroid tissue and cell cultures with the QIAGEN total RNA isolation kit in accordance with the manufacturer’s instructions. Genomic DNA was digested with 0.02 U deoxyribonuclease/µg RNA (Roche Molecular Biochemicals, Mannheim, Germany) at 25 C for 10 min. Five micrograms of total RNA were taken to synthesize cDNA, using a first-strand cDNA synthesis kit from Amersham Pharmacia Biotech (Freiburg, Germany) in a reaction volume of 15 µL.
Semiquantitative competitive RT-PCR
Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) cDNA was
quantified in accordance with the published method (15).
To quantify human SDF-1, CXCR4, and CD18 cDNA, a rapid one-step method
was introduced to synthesize an internal homologous competitor
(16, 17). For example, amplification of thyroid tissue
cDNA with the SDF-1 sense and SDF-1 hybrid primer (Table 2) resulted in a 209-bp SDF-1 competitor.
The competitor was purified from excess primers and deoxy-NTPs using
the QIAquick Gel Extraction Kit (QIAGEN) and quantified.
The competitors were stabilized at defined concentrations in the PCR
tubes using the method devised by Köhler et al.
(18).
|
CXCR4 receptor analysis in flow cytometry
To determine CXCR4 expression within the CD3+ and CD3- lymphocyte fractions, 2 x 105 thyroid-derived or peripheral blood lymphocytes from the same patient (n = 4) were stained with directly fluorochrome-labeled antibodies at the desired concentration for 25 min at 4 C (CXCR4-PE, CD3-Cy5, PharMingen Deutschland GmbH, Hamburg, Germany). The cells were washed three times with PBS/1% FCS and analyzed by flow cytometry in a FACScan (Becton Dickinson and Co.).
Immunohistology
SDF-1 expression was further examined on thyroid tissues by
immunohistology. Briefly, cryostat sections (5 µm thick) were fixed
in acetone (7 min). Endogenous peroxidase activity was quenched in
0.3% H2O2 in methanol for
20 min. The sections were stained with unlabeled anti-SDF-1 (clone
7901B,111; R & D Systems), or anti-CD45 (DAKO Corp., Hamburg, Germany) mouse monoclonal antibodies followed by
goat antimouse-biotin and streptavidin-horseradish peroxidase (ABC
standard, Vector Laboratories, Inc., Burlingame, CA) and
developed with diaminobenzidine (Vector Laboratories, Inc.). The anti-SDF-1 antibody detects an antigen shared by
SDF-1 and SDF-1ß. Blocking controls, preincubating 1 µg antibody
with 50 ng SDF-1, were included.
Results
SDF-1, CXCR4 mRNA, and CD18 mRNA levels in thyroid tissues
All thyroid tissues investigated were SDF-1 and CXCR4 mRNA
positive (Fig. 1). The SDF-1 mRNA levels
did not correlate with leukocyte infiltration, as determined by CD18
mRNA quantitation. The SDF-1 mRNA levels differed significantly between
autonomous single adenomas and the corresponding normal tissue
(P < 0.005) in TA patients. The SDF-1 mRNA levels in
autonomous single adenomas were also significantly lower than those in
GD tissues (P < 0.05), whereas the normal tissue from
TA patients and GD tissues expressed nearly the same level of SDF-1
mRNA. Only 1 of 11 TA patients showed a higher SDF-1 mRNA level in the
nodule compared with the normal tissue. In GD, TPO and anti-TBII
antibody levels did not correlate with the SDF-1 mRNA level. We found a
strong correlation between the CXCR4 and CD18 mRNA levels in GD tissues
(r = 0.9; P < 0.0001). CXCR4 mRNA levels further
correlated with anti-TPO (r = 0.81; P < 0.001),
but not with the TBII (r = 0.41; P = 0.04)
antibody levels. CXCR4 mRNA levels did not differ in autonomous nodules
and their corresponding quiescent tissue.
|
To define the cellular source of SDF-1 mRNA, we investigated
isolated thyroid-derived cell populations. Determination of SDF-1
and SDF-1ß in parallel revealed a higher expression of the SDF-1
in all SDF-1-positive cell types.
Fibroblasts expressed a higher basal SDF-1 mRNA level than thyrocytes.
Both cell types secreted SDF-1 under basal conditions (Figs. 2 and 3).
PMA decreased SDF-1 mRNA and protein only in fibroblasts, but caused a
dramatic increase in thyrocytes. IL-1 and TNF did not stimulate
SDF-1 secretion significantly. Thyroid-derived lymphocytes showed
weak SDF-1 mRNA expression, but no basal SDF-1 secretion. Only
lipopolysaccharide stimulated SDF-1 secretion, indicating the presence
of CD14+ monocytes/macrophages within the
leukocyte fraction (data not shown).
|
|
secretion (data not shown). SW1736 cells expressed
high basal SDF-1 (925 x
10-20 mol SDF-1 cDNA/PCR)
mRNA and protein under basal conditions (Fig. 4). PMA decreased SDF-1 mRNA and protein
in the cell lines significantly.
|
Immunostaining of serial thyroid tissue sections partly confirmed
the results obtained from isolated intrathyroidal cell populations.
SDF-1 was localized in stromal cells that were negative for the
leukocyte common antigen (CD45). Thus, fibroblasts expressed SDF-1
(Fig. 5A). Preincubation of the
anti-SDF-1 antibody with SDF-1 completely abolished immunostaining
(Fig. 5B). The epithelial cells in all thyroid specimens examined, with
a few exceptions, were completely SDF-1 negative. In contrast, cultured
thyrocytes secreted SDF-1. CD45+ leukocytes
failed to express SDF-1; although in GD, some leukocytes within areas
with high leukocytic infiltration were slightly positive for the
chemokine (Fig. 5, C and D). Additionally, SDF-1 was uniformly present
in endothelial cells of varying blood vessel types (data not
shown).
|
Thyroid-derived lymphocytes expressed CXCR4 mRNA (n =
3; mean ± SEM; 5.6 ± 0.7 x
10-18 CXCR4 cDNA/PCR;
Fig. 6). Thyrocytes (1.3 ±
0.2 x 10-20 CXCR4
cDNA/PCR) and fibroblasts (2.5 ± 0.5 x
10-20 CXCR4 cDNA/PCR)
showed a CXCR4 mRNA signal more than 500 times lower than that of
thyroid-derived lymphocytes, mainly due to contamination by a few
lymphocytes. Among the cell lines, only 8505C cells were CXCR4 mRNA
positive (14.1 ± 0.2 x
10-20 CXCR4 cDNA/PCR; Fig. 6). These results correlated well with the data obtained by flow
cytometry. Fibroblasts, thyrocytes, as well as most of the cell lines
did not express CXCR4. CXCR4 was found on the surface of roughly a
fourth of 8505C cells (data not shown). Double labeling CXCR4 and CD3
as a marker for T cells on peripheral blood and thyroid-derived
lymphocytes from the same patients (Fig. 7) revealed that the number of
CXCR4+ T cells in the thyroid was significantly
higher (CXCR4+ within CD3+,
mean ± SEM, 92.0 ± 3.2%) than the number in
the peripheral blood (CXCR4+ within
CD3+, 60.8 ± 6.0%; P <
0.01).
|
|
Autonomous nodules contained significantly lower SDF-1 mRNA levels compared with the corresponding normal tissue of the same patient. The difference is not due to variable leukocytic infiltration between the two tissue sites. This fact raises a question about the function of SDF-1 in normal and pathological thyroid tissue.
Lost or reduced expression of SDF-1 has been described in colonic adenomas and in hepatocellular, colon, esophageal, and gastric cancers (5, 6). The researchers suggest a role for SDF-1 in the initiation or progression of benign and malignant tumors. However, it is unlikely that the degree of SDF-1 mRNA loss indicates the malignant potential, as no correlation between them has been found. Reduction of SDF-1 mRNA expression probably occurs early in the adenoma-carcinoma sequence in colon carcinogenesis. Thus, SDF-1 may be a factor that is highly expressed in normal tissues to maintain normal architecture. As pointed out by Baggiolini (19), the chemoattractant properties of SDF-1 are useful during morphogenesis to keep similar cells together and to provide tissue homeostasis. It is unclear whether this SDF-1 mRNA reduction in thyroid adenomas is the result or the cause of the development of a new tissue organization while still maintaining follicles as the normal thyroid gland does. Autonomous thyroid nodules are characterized by increased epithelial proliferation independent of their histopathological or molecular characteristics compared with both the tissue surrounding the nodule and normal thyroid tissue (20, 21). Based on our finding that fibroblasts are the main producers of SDF-1 in the thyroid, a lower amount of stromal cells may be the cause of lower SDF-1 expression in autonomous nodules compared with that in the related normal thyroid.
SDF-1 possesses the highest capacity among chemokines to promote the attraction and arrest of circulating T lymphocytes on the luminal side of vascular endothelium for their recruitment into normal tissues (22). Moreover, SDF-1 may have a concentration-dependent bifunctional effect on T cell migration, attracting at one concentration and repulsing at another, as recently reported (23). Current results obtained in rheumatoid arthritis strongly imply that the interaction between SDF-1 and CXCR4 plays an important role in T cell accumulation in the inflamed synovium (24). SDF-1 may present a specific T cell-recruiting function during the onset, but not in the later course, of GD. To clarify this question, fine needle biopsies of thyroid tissue would be useful. However, there is no indication for thyroid biopsy material from GD patients. The function of SDF-1 in the thyroid may go beyond the regulation of leukocyte migration, as we found no correlation between the SDF-1 mRNA level and leukocyte infiltration in GD tissues where marked differences in CD18 mRNA expression were evident. Leukocyte infiltrates are not only maintained by continued attraction from the peripheral blood, but also by proliferation in the thyroid (25). However, SDF-1 is not involved in T cell proliferation, as it is unable to support IL-2 production and T cell proliferation either alone or in combination with coactivators, although SDF-1 can couple to distinct pathways that mediate cell survival, growth, and transcriptional activation.
The difference in SDF-1 mRNA levels in GD tissues with low or high leukocyte infiltration contrasts with our recently published results on RANTES, a CC chemokine that chemoattracts mainly CD45R0+ T memory cells and monocytes (26). Thyroid tissue of GD patients with high lymphocytic infiltration showed significantly higher RANTES mRNA levels than those with low infiltration. SDF-1 and RANTES were produced by different cellular sources. Only thyroid-derived lymphocytes were identified as potential producers of RANTES in the thyroid, whereas in the case of SDF-1, lymphocytes seemed the only cell population without or low SDF-1 production, as determined in vitro and by immunohistology. In situ, thyrocytes expressed SDF-1 at very low density or were SDF-1 negative, although the chemokine is strongly induced during in vitro culture. In accordance with the thyrocyte results, we found variable expression of SDF-1 in thyroid carcinoma cell lines. Four of five cell lines contained no, low, or moderate SDF-1 mRNA, supporting the study by Begum et al. (5), who reported that in Northern blots SDF-1 mRNA is absent from 27 human different malignant cell lines. However, unstimulated SW1736 thyroid carcinoma cells secreted even higher SDF-1 amounts than fibroblasts.
All thyroid tissues were SDF-1 mRNA positive, which was caused by basal
SDF-1 expression in thyrocytes and fibroblasts. This supports known
data on an the constitutive presence of SDF-1 in a wide range of
tissues. Most of the secreted SDF-1 is of the - and not ß-isoform,
as shown by different ELISA systems. The missing correlation between
the basal mRNA and protein levels in fibroblasts and thyrocytes is an
unexpected result. Fibroblasts showed a high SDF-1 mRNA level and
moderate SDF-1 secretion, which were confirmed by immunohistology. The
basal SDF-1 mRNA level in thyrocytes was 10- to 100-fold lower, but
they secreted equal amounts of SDF-1. This discrepancy may be based on
different posttranscriptional regulation mechanisms in both cell types.
IL-1 and TNF, proinflammatory cytokines that have been shown to be
expressed in the thyroid, did not significantly increase SDF-1
expression in fibroblasts, thyrocytes, and the carcinoma cell lines.
This represents a difference from most other chemokines, the production
of which is strongly augmented by proinflammatory stimuli
(27). As known from other studies, PMA down-regulated
SDF-1 in fibroblasts and carcinoma cell lines, but, surprisingly,
up-regulated SDF-1 in thyrocytes.
The distribution of CXCR4 in the thyroid completely differed from that of its ligand SDF-1. CXCR4 is present in thyroid-derived leukocytes. As shown in flow cytometry, CXCR4 is expressed at a higher number on thyroid-derived T-cells compared with peripheral T cells of the same patient. Recently, CXCR4 was shown to be expressed at significantly higher amounts in total CD45RA+ naive cells compared with CD45R0+ memory cells in the peripheral blood. However, in the thyroid, the higher amount of CD45R0+ memory cells is coupled with a higher amount of CXCR4+ cells. This result agrees with the study by Nanki et al. (24), who found that CXCR4 was markedly up-regulated on CD4+ T cells from synovial tissue compared with that expressed by peripheral CD4+ T cells. Peripheral T cells expressing CXCR4 may be selected for migration into the thyroid, or CXCR4 may be up-regulated during and/or after migration into the thyroid. PMA decreased CXCR4 on thyroid-derived lymphocytes, which is probably caused by receptor internalization (28). As shown by flow cytometry, thyrocytes do not carry CXCR4, although other epithelial cells, such as intestinal and type II alveolar cells, reportedly expressed CXCR4 and thus may serve as targets for chemokine signaling (29, 30, 31). Intestine, as well as lung epithelial cells carrying CXCR4, are particularly important, as they comprise an interface between the body and the environment. These epithelial cells must have the capacity to generate strong inflammatory responses to provide prompt leukocyte attraction for clearance of offending agents. CXCR4 expression does not seem so important for thyroid epithelial cells.
Taken together, SDF-1 seems to be involved in normal thyroid tissue homeostasis, but not in the maintenance of leukocyte infiltration. To further address the role of SDF-1 in the thyroid, the following experiments may be useful: calcium mobilization assay in response to SDF-1 stimulation on thyroid-derived cells, SDF-1-stimulated migration assay with peripheral and thyroid-derived T cells as well as thyrocytes, and measuring the influence of SDF-1 on activation-induced apoptosis in peripheral and thyroid-derived T cells.
Acknowledgments
We thank Mrs. D. Sittig for her excellent technical assistance and Prof. K. Spanel-Borowski for her support and advice.
Footnotes
1 This work was supported by the Interdisciplinary Center of Clinical
Research (IZKF, project B6), University of Leipzig. 
Received October 3, 2000.
Revised February 23, 2001.
Accepted March 1, 2001.
References
mRNA and protein in pathological thyroid tissue and carcinoma
cell lines. Clin Exp Immunol. 105:148–154.[CrossRef][Medline]
and TNF-. J Endocrinol. 151:277–285.
producing thyroid-derived T cells are detected in
Graves’ disease, thyroid autonomy as well as in non-toxic multinodular
goiter. Eur J Endocrinol. 135:60–68.This article has been cited by other articles:
 |
|
 |
|
  A. Ottaiano, R. Franco, A. Aiello Talamanca, G. Liguori, F. Tatangelo, P. Delrio, G. Nasti, E. Barletta, G. Facchini, B. Daniele, et al. Overexpression of Both CXC Chemokine Receptor 4 and Vascular Endothelial Growth Factor Proteins Predicts Early Distant Relapse in Stage II-III Colorectal Cancer Patients. Clin. Cancer Res., May 1, 2006; 12(9): 2795 - 2803. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. G. Narducci, E. Scala, A. Bresin, E. Caprini, M. C. Picchio, D. Remotti, G. Ragone, F. Nasorri, M. Frontani, D. Arcelli, et al. Skin homing of Sezary cells involves SDF-1-CXCR4 signaling and down-regulation of CD26/dipeptidylpeptidase IV Blood, February 1, 2006; 107(3): 1108 - 1115. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G Aust, K Krohn, N G Morgenthaler, S Schroder, A Schutz, J Edelmann, and E Brylla Graves' disease and Hashimoto's thyroiditis in monozygotic twins: case study as well as transcriptomic and immunohistological analysis of thyroid tissues Eur. J. Endocrinol., January 1, 2006; 154(1): 13 - 20. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G Aust, M Kamprad, P Lamesch, and E Schmucking CXCR6 within T-helper (Th) and T-cytotoxic (Tc) type 1 lymphocytes in Graves' disease (GD) Eur. J. Endocrinol., April 1, 2005; 152(4): 635 - 643. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Scala, A. Ottaiano, P. A. Ascierto, M. Cavalli, E. Simeone, P. Giuliano, M. Napolitano, R. Franco, G. Botti, and G. Castello Expression of CXCR4 Predicts Poor Prognosis in Patients with Malignant Melanoma Clin. Cancer Res., March 1, 2005; 11(5): 1835 - 1841. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. P. Martin, E. C. Coronel, G.-i. Sano, S.-C. Chen, G. Vassileva, C. Canasto-Chibuque, J. D. Sedgwick, P. S. Frenette, M. Lipp, G. C. Furtado, et al. A Novel Model for Lymphocytic Infiltration of the Thyroid Gland Generated by Transgenic Expression of the CC Chemokine CCL21 J. Immunol., October 15, 2004; 173(8): 4791 - 4798. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Nagashima, D. G. Silva, N. Petrovsky, L. A. Socha, H. Suzuki, R. Saito, T. Kasukawa, I. V. Kurochkin, A. Konagaya, and C. Schonbach Inferring Higher Functional Information for RIKEN Mouse Full-Length cDNA Clones With FACTS Genome Res., June 1, 2003; 13(6): 1520 - 1533. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. H. Hwang, J. H. Hwang, H. K. Chung, D. W. Kim, E. S. Hwang, J. M. Suh, H. Kim, K.-H. You, O-Y. Kwon, H. K. Ro, et al. CXC Chemokine Receptor 4 Expression and Function in Human Anaplastic Thyroid Cancer Cells J. Clin. Endocrinol. Metab., January 1, 2003; 88(1): 408 - 416. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 P. Romagnani, M. Rotondi, E. Lazzeri, L. Lasagni, M. Francalanci, A. Buonamano, S. Milani, P. Vitti, L. Chiovato, M. Tonacchera, et al. Expression of IP-10/CXCL10 and MIG/CXCL9 in the Thyroid and Increased Levels of IP-10/CXCL10 in the Serum of Patients with Recent-Onset Graves' Disease Am. J. Pathol., July 1, 2002; 161(1): 195 - 206. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. S. Taichman, C. Cooper, E. T. Keller, K. J. Pienta, N. S. Taichman, and L. K. McCauley Use of the Stromal Cell-derived Factor-1/CXCR4 Pathway in Prostate Cancer Metastasis to Bone Cancer Res., March 1, 2002; 62(6): 1832 - 1837. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Endocrinology | Endocrine Reviews | J. Clin. End. & Metab. |
| Molecular Endocrinology | Recent Prog. Horm. Res. | All Endocrine Journals |
200 U/mL; n = 8) and high
(
4000 U/mL; n = 8) levels of anti-TPO antibodies in serum. C,
Correlation between CXCR4 and CD18 mRNA levels in tissues affected by
GD (n = 16).
