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1.
Internalization of the Hyaluronan Receptor CD44 by Chondrocytes 总被引:1,自引:0,他引:1
Chondrocytes express CD44 as a primary receptor for the matrix macromolecule hyaluronan. Hyaluronan is responsible for the retention and organization of proteoglycan within cartilage, and hyaluronan-chondrocyte interactions are important for the assembly and maintenance of the cartilage matrix. Bovine articular chondrocytes were used to study the endocytosis and turnover of CD44 and the effects of receptor occupancy on this turnover. Matrix-intact chondrocytes exhibit approximately a 6% internalization of cell surface CD44 by 4 h. Treatment with Streptomyces hyaluronidase to remove endogenous pericellular matrix increased internalization to approximately 20% of cell surface CD44 at 4 h. This turnover could be partially inhibited by the addition of exogenous hyaluronan to these matrix-depleted chondrocytes. Cell surface biotin-labeled CD44 was internalized by chondrocytes and this internalization was decreased in the presence of hyaluronan. Colocalization of internalized CD44 and fluorescein-labeled hyaluronan in intracellular vesicles correlates with the previous results of receptor-mediated endocytosis pathway for the degradation of hyaluronan by acid hydrolases. Taken together, our results indicate that CD44 is internalized by chondrocytes and that CD44 turnover is modulated by occupancy with hyaluronan. 相似文献
2.
Hanna Siiskonen Kari T?rr?nen Timo Kumlin Kirsi Rilla Markku I. Tammi Raija H. Tammi 《The journal of histochemistry and cytochemistry》2011,59(10):908-917
Chronic intense UV radiation is the main cause of epidermal tumors. Because hyaluronan (HA), a large extracellular polysaccharide, is known to promote malignant growth, hyaluronan expression was studied in a model in which long-term UV radiation (UVR) induces epidermal tumors. Mouse back skin was exposed three times a week for 10.5 months to UVR corresponding to one minimal erythema dose, processed for histology, and stained for hyaluronan and the hyaluronan receptor CD44. This exposure protocol caused epidermal hyperplasia in most of the animals; tumors, mainly squamous cell carcinomas (SCCs), were found in ~20% of the animals. Specimens exposed to UVR showed increased hyaluronan and CD44 staining throughout the epidermal tissue. In hyperplastic areas, hyaluronan and CD44 stainings correlated positively with the degree of hyperplasia. Well-differentiated SCCs showed increased hyaluronan and CD44 staining intensities, whereas poorly differentiated tumors and dysplastic epidermis showed areas where HA and CD44 were locally reduced. The findings indicate that HA and CD44 increase in epidermal keratinocytes in the premalignant hyperplasia induced by UV irradiation and stay elevated in dysplasia and SCC, suggesting that the accumulation of hyaluronan and CD44 is an early marker for malignant transformation and may be a prerequisite for tumor formation. 相似文献
3.
Jayne Lesley Robert Hyman Nicole English Jonathan B Catterall Graham A Turner 《Glycoconjugate journal》1997,14(5):611-622
CD44 is a major cell surface receptor for the glycosaminoglycan, hyaluronan (HA). CD44 binds HA specifically, although certain
chondroitin-sulfate containing proteoglycans may also be recognized. CD44 binding of HA is regulated by the cells in which
it is expressed. Thus, CD44 expression alone does not correlate with HA binding activity. CD44 is subject to a wide array
of post-translational carbohydrate modifications, including N-linked, O-linked and glycosaminoglycan side chain additions.
These modifications, which differ in different cell types and cell activation states, can have profound effects on HA binding
function and are the main mechanism of regulating CD44 function that has been described to date. Some glycosaminoglycan modifications
also affect ligand binding specificity, allowing CD44 to interact with proteins of the extracellular matrix, such as fibronectin
and collagen, and to sequester heparin binding growth factors. It is not yet established whether the HA binding function of
CD44 is responsible for its proposed involvement in inflammation. It has been shown, however, that CD44/HA interactions can
mediate leukocyte rolling on endothelial and tissue substrates and that CD44-mediated recognition of HA can contribute to
leukocyte activation. Changes in CD44 expression (mainly up-regulation, occasionally down-regulation, and frequently alteration
in the pattern of isoforms expressed) are associated with a wide variety of cancers and the degree to which they spread; however,
in other cancers, the CD44 pattern remains unchanged. Increased expression of CD44 is associated with increased binding to
HA and increased metastatic potential in some experimental tumor systems; however, in other systems increased HA binding and
metastatic potential are not correlated. CD44 may contribute to malignancy through changes in the regulation of HA recognition,
the recognition of new ligands and/or other new biological functions of CD44 that remain to be discovered. Abbreviations:
aa, amino acid(s); CS, chondroitin sulfate; CSPG, chondroitin sulfate containing proteoglycan; CD44H, ‘hematopoietic’, also
called ‘standard’, isoform of CD44 which contains none of the alternatively spliced variant exons; CD44-Rg, CD44 receptor
globulin, a secreted chimaeric protein composed of the external domain of the adhesion receptor CD44 and the hinge, CH2 and
CH3 regions of human immunoglobulin-G heavy chain; ECM, extracellular matrix; GAG, glycosaminoglycan; HA, hyaluronan; HS,
heparan sulfate; KS, keratan sulfate; PB, peripheral blood; PBL, peripheral blood lymphocytes
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
4.
Yoshihiro Tokudome Kyosuke Nakamura Fumie Hashimoto 《Bioscience, biotechnology, and biochemistry》2013,77(6):1018-1021
Low molecular weight soybean peptide (LSP) was applied to normal human epidermal keratinocytes, and the results showed a significant increase in the gene expression levels of involucrin, transglutaminase, and profilaggrin. Filaggrin protein levels were also significantly higher. It is possible that LSP has an epidermal cell differentiation-promoting effect and may be able to regulate metabolism of the epidermis. 相似文献
5.
Differential expression of CD44 during human prostate epithelial cell differentiation. 总被引:1,自引:0,他引:1
Tahirah N Alam Michael J O'Hare István Laczkó Alex Freeman Farah Al-Beidh John R Masters David L Hudson 《The journal of histochemistry and cytochemistry》2004,52(8):1083-1090
CD44 is a polymorphic transmembrane glycoprotein that binds hyaluronan and growth factors. Multiple isoforms of the protein can be generated by alternative splicing but little is known about the expression and function of these isoforms in normal development and differentiation. We have investigated the expression of CD44 during normal prostate epithelial cell differentiation. A conditionally immortalized prostate epithelial cell line, Pre2.8, was used as a model system. These cells proliferate at 33C but at 39C stop dividing and undergo changes consistent with early stages of cell differentiation. During the differentiation of these cells, the expression of the CD44 isoform v3-v10 was upregulated. Two layers of epithelial cells can clearly be distinguished in the human prostate, a basal layer expressing keratins 5/14 and a luminal layer expressing keratins 8/18. In prostate tissue the v3-v10 isoform was found predominantly in basal cells but also in keratin 14-negative, keratin 19-positive cells intermediate between the two layers. CD44 v3-v10 was also expressed in other keratin 14-negative prostate tissues, the ejaculatory ducts and prostatic urethra. Therefore, CD44 v3-v10 may be important as a cell surface marker for differentiating cells in the prostate epithelium. 相似文献
6.
7.
Variant isoforms of the cell surface glycoprotein CD44 (CD44v) are expressed during development, in selected adult tissues and in certain metastatic tumor cells. CD44v differ from the standard isoform (CD44s) by up to ten additional exon sequences included by alternative splicing. By cell fusion experiments, we have obtained evidence for the existence of cell-type specific trans-acting factors recruiting CD44 variant exon sequences. Stable cell hybrids of CD44s and CD44v expressing cells indicated a dominant mechanism for variant-exon inclusion. In transient interspecies heterokaryons of human keratinocytes and rat fibroblasts, the ability of the keratinocytes to include all variant exon sequences in CD44 was conferred completely on the rat fibroblast nucleus. Fusions of cells with complex CD44 splice patterns do not permit interpretation of splice control by the relative abundance of a single trans-acting factor, but rather by (a) positively acting factor(s) recruiting variant exon sequences in the 3' to 5' direction and additional factors selecting individual exons. Since the pancreatic carcinoma cell line BSp73ASML (in contrast to the cervix carcinoma cell lines SiHa and ME180) could not transfer its specific splice pattern in cell fusions, we conclude that in some tumors, splicing is also controlled by mutation of cis-acting recognition sites. 相似文献
8.
9.
Hyaluronan, a high-molecular-weight glycosaminoglycan of the extracellular matrix, is prominent during rapid tissue growth and repair. It stimulates cell motility and hydrates tissue, providing an environment that facilitates cell movement. Markedly enhanced levels of hyaluronan also occur in the stroma surrounding human cancers, thus providing an environment that promotes spread of cancer cells. The ability of malignant tumors to generate lactate, even in the presence of adequate oxygen, is known as the Warburg effect. Early in wound healing as blood and oxygen supply decrease, lactate levels increase, as does stromal hyaluronan, suggesting a cause-and-effect relationship. Similarly, peritumor stromal fibroblast hyaluronan may be a response to cancer cell lactate. To test this, fibroblasts were cultured in the presence of lactate. With increasing lactate, higher levels of hyaluronan were observed, as were levels of CD44 expression, the predominant receptor for hyaluronan. The ability of tumor cells to utilize anaerobic metabolism and to generate lactate, even in the presence of adequate supplies of oxygen, may be one of the mechanisms used to recruit host fibroblasts to deposit hyaluronan and to express CD44, thereby participating in the process of cancer invasion and metastasis. 相似文献
10.
Acylceramides and lanosterol-lipid markers of terminal differentiation in cultured human keratinocytes: Modulating effect of retinoic acid 总被引:1,自引:0,他引:1
J. Brod E. Bavelier P. Justine A. Weerheim M. Ponec 《In vitro cellular & developmental biology. Animal》1991,27(2):163-168
Summary Epidermal differentiation is accompanied by profound changes in the synthesis of a variety of intracellular proteins and intercellular
lipids. In conventional, submerged culture keratinocytes have been shown to lose the ability to synthesize the protein markers
of differentiation. They re-express them, however, when they are cultured in medium supplemented with delipidized [retinoic
acid (RA)-depleted] serum or in air-exposed cultures using de-epidermized dermis (DED) as a substrate. Recent studies have
revealed that acylceramides (AC) and lanosterol (LAN), which are present only in trace amounts in cultures of keratinocytes
grown under submerged conditions on DED in medium supplemented with normal serum, become expressed in significant amounts
when the culture is lifted to the air-liquid interface. Inasmuch as culture conditions may markedly affect the extent of keratinocyte
differentiation, the present study aimed to investigate the effect of normal (RA-containing) or delipidized (RA-depleted)
serum and of RA administration on lipid composition (especially of the AC and LAN contents) in cells cultured under submerged
and air-exposed conditions. To test a possible effect of dermal substrate (used in the air-exposed model), the lipid composition
of keratinocytes grown under submerged conditions on a plastic and on a dermal substrate (de-epidermized dermis, DED) has
also been compared. The results revealed that under all culture conditions, RA deprivation of fetal bovine serum resulted
in a marked increase of total ceramide content. Even under submerged conditions, the presence of both AC and LAN could be
detected. In air-exposed culture, the content of these lipids was markedly increased. Addition of RA at 1 μM concentration to cultures grown in RA-depleted medium induced marked changes in lipid composition under all culture conditions
tested. In cells grown under submerged conditions (both on plastic and on DED) AC and LAN were no longer present in detectable
amounts. Also in air-exposed culture, a marked decrease in the content of these lipids was observed. These results suggest
that liposoluble serum components, like RA, control the synthesis of lipids that are present in later stages of epidermal
differentiation. 相似文献
11.
Nicola Nylander Lynne T. Smith Robert A. Underwood Michael Piepkorn 《In vitro cellular & developmental biology. Animal》1998,34(2):182-188
Summary Much of the autonomous growth of cultured keratinocytes is attributable to the signaling of amphiregulin, a heparin-binding
autocrine growth factor, through the epidermal growth factor receptor. Emerging evidence suggests, moreover, that the membrane
proteoglycan, CD44, is a cofactor for the interaction of heparin-binding ligands with their receptors. This model was evaluated
by characterizing the patterns of the immunolabeled molecules in cultured human neonatal keratinocytes, to test the hypothesis
that involvement in a common function results in coordinate segregation within or on the cell. The molecules were localized
by double immunofluorescence labeling to detect amphiregulin and either the epidermal growth factor receptor or CD44, and
the immunostained products were imaged by scanning laser confocal microscopy. Both amphiregulin and the epidermal growth factor
receptor segregated to a perinuclear distribution and to intercellular contacts. In addition, amphiregulin localized to the
outer leading edge of colonies and focally to intranuclear sites. Metabolic blockade of proteoglycan sulfation with sodium
chlorate inhibited growth of the cells and concurrently enhanced the nuclear, but decreased the outer leading edge, labeling
for amphiregulin. There was no nuclear or perimeter labeling for the epidermal growth factor receptor. Cultures co-immunolabeled
for CD44 and amphiregulin exhibited variable perinuclear staining for both, but otherwise CD44 was distributed to intercellular
contacts. The intercellular localizations of CD44 with amphiregulin and of amphiregulin with the epidermal growth factor receptor
were strongly concordant. These data are consistent with a concerted function at intercellular contacts, where cytokine signaling
is mediated via receptor binding and possibly regulated by the CD44 proteoglycan as cofactor. The intranuclear and perimeter
labeling of amphiregulin, however, suggests that this cytokine has additional functions, both in the nucleus and as a matrix
receptor. 相似文献
12.
K Fuchs A Hippe A Schmaus B Homey J P Sleeman V Orian-Rousseau 《Cell death & disease》2013,4(10):e819
The tumor microenvironment makes a decisive contribution to the development and dissemination of cancer, for example, through extracellular matrix components such as hyaluronan (HA), and through chemokines that regulate tumor cell behavior and angiogenesis. Here we report a molecular link between HA, its receptor CD44 and the chemokine CXCL12 in the regulation of cell motility and angiogenesis. High-molecular-weight HA (hHA) was found to augment CXCL12-induced CXCR4 signaling in both HepG2iso cells and primary human umbilical vein endothelial cells, as evidenced by enhanced ERK phosphorylation and increased cell motility. The augmentation of CXCR4 signaling translated into increased vessel sprouting and angiogenesis in a variety of assays. Small HA oligosaccharides (sHA) efficiently inhibited these effects. Both siRNA-mediated reduction of CD44 expression and antibodies that block the interaction of CD44 with HA provided evidence that CXCL12-induced CXCR4 signaling depends on the binding of hHA to CD44. Consistently, CD44 and CXCR4 were found to physically interact in the presence of CXCL12, an interaction that could be inhibited by sHA. These findings provide novel insights into how microenvironmental components interact with cell surface receptors in multi-component complexes to regulate key aspects of tumor growth and progression. 相似文献
13.
The challenges of measuring optical properties of human tissues include the thickness of the sample, homogenization, or crystallization from freezing of the tissue. This investigation demonstrates a method to avoid these problems by growing optically thin samples of human keratinocytes as a substitute for ex vivo epidermis samples. Several methods of growth were investigated. Resulting samples were measured on a spectrophotometer for transmission between 300 nm and 2600 nm. The efficacy of the cell growth was confirmed with histological examination of several cultured keratinocyte samples. Limitations were the requirement to measure samples immediately after removal from the incubation environment, and the absence of the irregular structures of normal skin such as hair and glands. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
14.
Patricia Ruiz Christoph Schwrzler Ursula Günthert 《BioEssays : news and reviews in molecular, cellular and developmental biology》1995,17(1):17-24
During mouse early development cell adhesion molecules are indispensable for the embryo organisation. A family of molecules probably involved in development is the transmembrane glycoprotein CD44 family, which exists in multiple isoforms. These are generated by alternative splicing of the pre-mRNA, resulting in the enlargement of the extracellular part of the molecule. The standard form of CD44 is widely expressed in adult tissues and in embryos from day 9.5 post coitum onwards, while the numerous variant isoforms exhibit highly specialised patterns of expression that are already in the egg cylinder at day 6.5 of development. In lymphohemopoiesis, specific variant isoforms also emerge at decisive differentiation stages. Although specific ligands for the variant region still await isolation, the highly organised expression of CD44 variant isoforms suggests they have a pivotal role in cellular interactions during early development, pattern formation and hemopoiesis. 相似文献
15.
CD44 regulates myoblast migration and differentiation 总被引:5,自引:0,他引:5
CD44 is a transmembrane protein that plays a role in cell-cell interactions and motility in a number of cell types. Cell-cell interactions are critical for myoblast differentiation and fusion but whether CD44 regulates myogenesis is unknown. Here, we show that CD44 plays a functional role in early myogenesis. Analyses of myofiber cross-sectional area, after local injury in mouse tibialis anterior (TA) muscles, revealed that growth was transiently delayed in the absence of CD44. A muscle-intrinsic role for CD44 is suggested as primary myoblasts from CD44(-/-) mice displayed attenuated differentiation and subsequent myotube formation at early times in a differentiation-inducing in vitro environment. Chemotaxis of CD44(-/-) myoblasts toward hepatocyte growth factor (HGF) and basic fibroblast growth factor (bFGF) was totally abrogated, although expression of their respective receptors did not appear to differ from wild-type. Furthermore, motility of CD44(-/-) myoblasts was decreased at early stages of differentiation as determined by time-lapse microscopy. Wild-type myoblasts contained two subpopulations of slow- and fast-migrating cells, whereas CD44(-/-) myoblasts were composed predominantly of the slower migrating subpopulation. Taken together, these data suggest that myoblast migration and differentiation are closely linked and CD44 is a key regulator. 相似文献
16.
Ezura Y Chakravarti S Oldberg A Chervoneva I Birk DE 《The Journal of cell biology》2000,151(4):779-788
Collagen fibrillogenesis is finely regulated during development of tissue-specific extracellular matrices. The role(s) of a leucine-rich repeat protein subfamily in the regulation of fibrillogenesis during tendon development were defined. Lumican-, fibromodulin-, and double-deficient mice demonstrated disruptions in fibrillogenesis. With development, the amount of lumican decreases to barely detectable levels while fibromodulin increases significantly, and these changing patterns may regulate this process. Electron microscopic analysis demonstrated structural abnormalities in the fibrils and alterations in the progression through different assembly steps. In lumican-deficient tendons, alterations were observed early and the mature tendon was nearly normal. Fibromodulin-deficient tendons were comparable with the lumican-null in early developmental periods and acquired a severe phenotype by maturation. The double-deficient mice had a phenotype that was additive early and comparable with the fibromodulin-deficient mice at maturation. Therefore, lumican and fibromodulin both influence initial assembly of intermediates and the entry into fibril growth, while fibromodulin facilitates the progression through growth steps leading to mature fibrils. The observed increased ratio of fibromodulin to lumican and a competition for the same binding site could mediate these transitions. These studies indicate that lumican and fibromodulin have different developmental stage and leucine-rich repeat protein specific functions in the regulation of fibrillogenesis. 相似文献
17.
18.
Emma L. Woods Irina V. Grigorieva Adam C. Midgley Charlotte V.M. Brown Yueh-an Lu Aled O. Phillips Timothy Bowen Soma Meran Robert Steadman 《The Journal of biological chemistry》2021,297(3)
Progressive fibrosis leads to loss of organ function and affects many organs as a result of excessive extracellular matrix production. The ubiquitous matrix polysaccharide hyaluronan (HA) is central to this through association with its primary receptor, CD44, which exists as standard CD44 (CD44s) or multiple splice variants. Mediators such as profibrotic transforming growth factor (TGF)-β1 and proinflammatory interleukin (IL)-1β are widely associated with fibrotic progression. TGF-β1 induces myofibroblast differentiation, while IL-1β induces a proinflammatory fibroblast phenotype that promotes fibroblast binding to monocyte/macrophages. CD44 expression is essential for both responses. Potential CD44 splice variants involved, however, are unidentified. The TGF-β1-activated CD44/epidermal growth factor receptor complex induces differentiation of metastatic cells through interactions with the matrix metalloproteinase inducer, CD147. This study aimed to determine the CD44 variants involved in TGF-β1- and IL-1β-mediated responses and to investigate the potential profibrotic role of CD147. Using immunocytochemistry and quantitative PCR, standard CD44s were shown to be essential for both TGF-β1-induced fibroblast/myofibroblast differentiation and IL-1β-induced monocyte binding. Co-immunoprecipitation identified that CD147 associated with CD44s. Using CD147-siRNA and confocal microscopy, we also determined that incorporation of the myofibroblast marker, αSMA, into F-actin stress fibers was prevented in the absence of CD147 and myofibroblast-dependent collagen gel contraction was inhibited. CD147 did not associate with HA, but removal of HA prevented the association of CD44s with CD147 at points of cell–cell contact. Taken together, our data suggest that CD44s/CD147 colocalization is essential in regulating the mechanical tension required for the αSMA incorporation into F-actin stress fibers that regulates myofibroblast phenotype. 相似文献
19.
20.
Growth and differentiation of human keratinocytes without a feeder layer or conditioned medium 总被引:1,自引:0,他引:1
Summary An improved procedure has been developed for clonal growth of normal human epidermal keratinocytes (HK) without feeder cells
or conditioned medium. The use of medium 199, supplemented with 0.4 μg/ml hydrocortisone (HC) and 20% (v/v) whole fetal bovine
serum (wFBS) and conditioned overnight by 3T3 cells, eliminated the need for a feeder layer of lethally irradiated 3T3 cells
for HK growth. Several other media with equivalent conditioning and supplementation failed to support satisfactory multiplication
of HK, including Dulbecco's modified Eagle's medium, which is normally used for growth of HK with a feeder layer. Increasing
the concentration of HC to 10 μg/ml (2.8×10−5
M) made possible clonal growth of HK without any conditioning of the medium. The addition of 10−5
M putrescine, 10−5
M vitamin B12, or 3.7×10−6
M β-estradiol further enhanced growth in unconditioned medium. Substantially greater improvement was obtained by the addition
of pituitary extract or fractions prepared from pituitary extract. In medium 199 supplemented with 10 μg/ml HC, 20% (v/v)
wFBS, and 0.15 mg/ml each of two pituitary fractions, single HK attach with a colony-forming efficiency equal to that in conditioned
medium and form stratified, keratinized colonies that grow to confluency and can be subcultured. These results make it clear
that HK do not require special “conditioning factors” from fibroblasts for clonal growth and differentiation in culture. Thus,
factors directly involved in growth and the expression of differentiation can be analyzed without the interfering effects
of any other type of cell. Preliminary studies with epidermal growth factor (EGF), which stimulates growth and extends life
span of HK grown in the presence of fibroblasts, have shown that, in the absence of fibroblasts, EGF has no effect either
on clonal growth or on cumulative multiplication potential of HK.
This paper contains material from a thesis submitted to the Graduate School of the University of Colorado, Boulder, by Donna
M. Peehl in partial fulfillment of the requirements for the Ph.D. degree.
This work was supported by Grant CA 15305 from the National Cancer Institute and Grant AG 00310 from the National Institute
on Aging. 相似文献