Restricted expression of the hyaluronan receptor, CD44, during postimplantation mouse embryogenesis suggests key roles in tissue formation and patterning

Development ◽  
1993 ◽  
Vol 119 (2) ◽  
pp. 295-306 ◽  
Author(s):  
S.C. Wheatley ◽  
C.M. Isacke ◽  
P.H. Crossley

CD44 is a multifunctional adhesion protein that acts as a major receptor for the hygroscopic extracellular matrix component, hyaluronan. This receptor-ligand binding directly mediates at least some of the cell-cell and cell-matrix interactions ascribed to CD44. Other interactions involving CD44 may be modulated indirectly by its ability to bind growth factors and thereby to promote cell attachment. During vertebrate development, multiple cases of hyaluronan involvement in cell proliferation, cell migration and histogenesis have been documented. In addition, there is evidence suggesting a central role for cell surface glycoproteins and proteoglycans in mediating the action of polypeptide growth factors involved in tissue patterning. In view of this, we undertook to investigate expression of the CD44 protein during postimplantation mouse embryogenesis. Between 9.5 and 12.5 days of embryonic development, the predominant form of CD44 protein corresponds to the hyaluronan-binding CD44H form. However, species with a higher M(r) were also detected, implying that CD44 isoforms generated by alternative splicing of CD44 RNA are employed in normal development. Further, we used mouse embryos to perform whole-mount immunohistochemistry and examine the temporal and spatial distribution of this glycoprotein. CD44 is expressed at high levels in the heart, somites and condensing limb-bud mesenchyme at critical stages of morphogenesis. These sites correlate with regions where hyaluronan has been demonstrated to regulate morphogenetic events. Of novel interest, however, is the high expression of CD44 in regions that do not correlate with sites of known hyaluronan-mediated developmental events. These include instructive epithelia participating in epithelial-mesenchymal cell interactions such as the apical ectodermal ridge of the developing limb bud and the odontogenic placodes of the presumptive upper and lower jaws.

1982 ◽  
Vol 112 (3) ◽  
pp. 353-359 ◽  
Author(s):  
Paul B. Kaplowitz ◽  
A. Joseph D'ercole ◽  
Louis E. Underwood

2021 ◽  
Vol 22 (12) ◽  
pp. 6241
Author(s):  
Roxanne N. Stone ◽  
Stephanie M. Frahs ◽  
Makenna J. Hardy ◽  
Akina Fujimoto ◽  
Xinzhu Pu ◽  
...  

Osteoarthritis is a major concern in the United States and worldwide. Current non-surgical and surgical approaches alleviate pain but show little evidence of cartilage restoration. Cell-based treatments may hold promise for the regeneration of hyaline cartilage-like tissue at the site of injury or wear. Cell–cell and cell–matrix interactions have been shown to drive cell differentiation pathways. Biomaterials for clinically relevant applications can be generated from decellularized porcine auricular cartilage. This material may represent a suitable scaffold on which to seed and grow chondrocytes to create new cartilage. In this study, we used decellularization techniques to create an extracellular matrix scaffold that supports chondrocyte cell attachment and growth in tissue culture conditions. Results presented here evaluate the decellularization process histologically and molecularly. We identified new and novel biomarker profiles that may aid future cartilage decellularization efforts. Additionally, the resulting scaffold was characterized using scanning electron microscopy, fluorescence microscopy, and proteomics. Cellular response to the decellularized scaffold was evaluated by quantitative real-time PCR for gene expression analysis.


2003 ◽  
Vol 162 (3) ◽  
pp. 499-509 ◽  
Author(s):  
Roberta Faccio ◽  
Deborah V. Novack ◽  
Alberta Zallone ◽  
F. Patrick Ross ◽  
Steven L. Teitelbaum

The β3 integrin cytoplasmic domain, and specifically S752, is critical for integrin localization and osteoclast (OC) function. Because growth factors such as macrophage colony–stimulating factor and hepatocyte growth factor affect integrin activation and function via inside-out signaling, a process requiring the β integrin cytoplasmic tail, we examined the effect of these growth factors on OC precursors. To this end, we retrovirally expressed various β3 integrins with cytoplasmic tail mutations in β3-deficient OC precursors. We find that S752 in the β3 cytoplasmic tail is required for growth factor–induced integrin activation, cytoskeletal reorganization, and membrane protrusion, thereby affecting OC adhesion, migration, and bone resorption. The small GTPases Rho and Rac mediate cytoskeletal reorganization, and activation of each is defective in OC precursors lacking a functional β3 subunit. Activation of the upstream mediators c-Src and c-Cbl is also dependent on β3. Interestingly, although the FAK-related kinase Pyk2 interacts with c-Src and c-Cbl, its activation is not disrupted in the absence of functional β3. Instead, its activation is dependent upon intracellular calcium, and on the β2 integrin. Thus, the β3 cytoplasmic domain is responsible for activation of specific intracellular signals leading to cytoskeletal reorganization critical for OC function.


1995 ◽  
Vol 128 (4) ◽  
pp. 687-698 ◽  
Author(s):  
K L Bennett ◽  
D G Jackson ◽  
J C Simon ◽  
E Tanczos ◽  
R Peach ◽  
...  

Glycosaminoglycan-modified isoforms of CD44 have been implicated in growth factor presentation at sites of inflammation. In the present study we show that COS cell transfectants expressing CD44 isoforms containing the alternatively spliced exon V3 are modified with heparan sulfate (HS). Binding studies with three HS-binding growth factors, basic-fibroblast growth factor (b-FGF), heparin binding-epidermal growth factor (HB-EGF), and amphiregulin, showed that the HS-modified CD44 isoforms are able to bind to b-FGF and HB-EGF, but not AR. b-FGF and HB-EGF binding to HS-modified CD44 was eliminated by pretreating the protein with heparitinase or by blocking with free heparin. HS-modified CD44 immunoprecipitated from keratinocytes, which express a CD44 isoform containing V3, also bound to b-FGF. We examined whether HS-modified CD44 isoforms were expressed by activated endothelial cells where they might present HS-binding growth factors to leukocytes during an inflammatory response. PCR and antibody-binding studies showed that activated cultured endothelial cells only express the CD44H isoform which does not contain any of the variably spliced exons including V3. Immunohistological studies with antibodies directed to CD44 extracellular domains encoded by the variably spliced exons showed that vascular endothelial cells in inflamed skin tissue sections do not express CD44 spliced variants. Keratinocytes, monocytes, and dendritic cells in the same specimens were found to express variably spliced CD44. 35SO4(-2)-labeling experiments demonstrated that activated cultured endothelial cells do not express detectable levels of chondroitin sulfate or HS-modified CD44. Our results suggest that one of the functions of CD44 isoforms expressing V3 is to bind and present a subset of HS-binding proteins. Furthermore, it is probable that HS-modified CD44 is involved in the presentation of HS-binding proteins by keratinocytes in inflamed skin. However, our data suggests that CD44 is not likely to be the proteoglycan principally involved in presenting HS-binding growth factors to leukocytes on the vascular cell wall.


1992 ◽  
Vol 262 (4) ◽  
pp. F523-F532 ◽  
Author(s):  
M. R. Hammerman ◽  
S. A. Rogers ◽  
G. Ryan

The formation of all organs during embryogenesis, including kidney, is dependent on the timed and sequential expression of a number of polypeptide growth factors. Synthesis and actions of one or more members of the insulin-like growth factor, epidermal growth factor/transforming growth factor-alpha, transforming growth factor-beta, platelet-derived growth factor, fibroblast growth factor, and nerve growth factor families have been characterized in the developing metanephric kidney. Studies originating from a number of laboratories have defined the localization of growth factor mRNAs, receptors and peptides, have delineated patterns of growth factor synthesis, and have established the growth factor dependency of embryonic kidney development. The results of these investigations will be summarized in this editorial review and integrated within the broader context of growth factor cellular physiology and growth factor expression in nonrenal systems.


1998 ◽  
Vol 111 (8) ◽  
pp. 1127-1135 ◽  
Author(s):  
A.J. Messent ◽  
D.S. Tuckwell ◽  
V. Knauper ◽  
M.J. Humphries ◽  
G. Murphy ◽  
...  

In this paper we show that collagenase-3 cleavage of type I collagen has a marked effect on alpha2beta1 integrin-mediated interactions with the collagen fragments generated. Isolated alpha2beta1 integrin and alpha2 integrin A-domain were found to bind to both native collagen and native 3/4 fragment and, to a lesser degree, native 1/4 fragment. Whole integrin and integrin A-domain binding were lost after heat denaturation of the collagen fragments. At physiological temperature, cell adhesion to triple-helical 3/4 fragment via alpha2beta1 integrin was still possible; however, no alpha2beta1 integrin-mediated adhesion to the 1/4 fragment was observed. Unwinding of the collagen fragment triple helices by heating to physiological temperatures prior to adsorption to plastic tissue culture plates resulted in total abrogation of HT1080 cell attachment to either fragment. These results provide significant evidence in support of a role for matrix-metalloproteinase cleavage of the extracellular matrix in modifying cell-matrix interactions.


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