Developmental Changes in Glycoconjugate Composition During Chick Lens Morphogenesis

Yao, Ruihong; Alcala, Jose; Maisel, H.

doi:10.1006/exer.1996.0047

Cited by 8 publications

(6 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…By analyzing the lectin binding capacity of this superficial coat, Zschä bitz et al (1994) demonstrated biochemical differences between the matrix that covers the MEE and other palatal epithelia, and suggested its importance in cell recognition and adhesion during palate fusion. Glycoprotein molecules have also been observed in the intercellular matrix interposed between the edges of the lens plate (Van Rybroeck and Olson, 1981;Yao et al, 1996) and the neural primordium (Smits Van Prooije et al, 1986;Trasler and Morriss-Kay, 1991) during their apposition, and there is experimental evidence showing that disruption in the synthesis or enzymatic degradation of these proteoglycans seriously disrupts the fusion process (Morriss-Kay and Crutch, 1982;Morriss-Kay and Tuckett, 1989;Alonso et al, 1998). Among the different proteoglycans that could form part of these glycoconjugates and have a role during palatal shelf adhesion, our recent demonstration of the presence of chondroitin sulphate proteoglycan (CSPG) covering the superficial bulging MEE cells (Martínez-Á lvarez et al, 2000b), strongly points to its direct participation in this mechanism.…”

Section: Introductionmentioning

confidence: 99%

TGF-β3-Induced Chondroitin Sulphate Proteoglycan Mediates Palatal Shelf Adhesion

Gato

Martínez

Tudela

et al. 2002

Developmental Biology

View full text Add to dashboard Cite

In mammals, the adhesion and fusion of the palatal shelves are essential mechanisms in the development of the secondary palate. Failure of any of these processes leads to the formation of cleft palate. The mechanisms underlying palatal shelf adhesion are poorly understood, although the presence of filopodia on the apical surfaces of the superficial medial edge epithelial (MEE) cells seems to play an important role in the adhesion of the opposing MEE. We demonstrate here the appearance of chondroitin sulphate proteoglycan (CSPG) on the apical surface of MEE cells only immediately prior to contact between the palatal shelves. This apical CSPG has a functional role in palatal shelf adhesion, as either the alteration of CSPG synthesis by beta-D-Xyloside or its specific digestion by chondroitinase AC strikingly alters the in vitro adhesion of palatal shelves. We also demonstrate the absence of this apical CSPG in the clefted palates of transforming growth factor beta 3 (TGF-beta(3)) null mutant mice, and its induction, together with palatal shelf adhesion, when TGF-beta(3) is added to TGF-beta(3) null mutant palatal shelves in culture. When chick palatal shelves (that do not adherein vivo nor express TGF-beta(3), nor CSPG in the MEE) are cultured in vitro, they do not express CSPG and partially adhere, but when TGF-beta(3) is added to the media, they express CSPG and their adhesion increases strikingly. We therefore conclude that the expression of CSPG on the apical surface of MEE cells is a key factor in palatal shelf adhesion and that this expression is regulated by TGF-beta(3).

show abstract

Section: Introductionmentioning

confidence: 99%

TGF-β3-Induced Chondroitin Sulphate Proteoglycan Mediates Palatal Shelf Adhesion

Gato

Martínez

Tudela

et al. 2002

Developmental Biology

View full text Add to dashboard Cite

show abstract

“…This suggests that CSPG might play a role in the recognition and adherence of the edges of the lens placode. In this regard it was demonstrated that glycoproteins are present in the intercellular matrix interposed between the edges of the lens placode during its apposition (Van Rybroek and Olson, 1981;Yao et al, 1996). Similarly, the presence of a matrix rich in glycoconjugates interposed in the epithelial fusion region was also reported during the fusion of other embryonal primordia such as the neurla tube (Smits-van-Prooije et al, 1986;Trasler and Morriss-Kay, 1991) and the palate (Martõ Ânez-Alvarez et al, 2000).…”

Section: Discussionmentioning

confidence: 92%

“…It has been postulated (Van Rybroek and Olson, 1981;Yao et al, 1996. ) that an apical`cell coat' rich in glycoconjugates might play a signi®cant role in lens epithelium invagination.…”

Section: Discussionmentioning

confidence: 97%

“…In relation to this matter, there are previous studies which reveal the presence of glycoconjugates and proteoglycans in lens vesicle development. The presence of glycoconjugates on the apical surface of the lens placode during invagination and fusion was demonstrated with histochemical and lectin techniques by Van Rybroek and Olson (1981), Webster and Uknis (1987) and Yao, Alcala and Maisel (1996). More speci®c studies relating to proteoglycan expression during early lens development were carried out by Haloui et al (1988).…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Chondroitin Sulphate Proteoglycan is Involved in Lens Vesicle Morphogenesis in Chick Embryos

Gato

Martín

Alonso

et al. 2001

Experimental Eye Research

View full text Add to dashboard Cite

Proteoglycans have been implicated in the invagination and formation of various embryonal cavitied primordia. In this paper the expression of chondroitin sulphate proteoglycan is analysed (CSPG) in the lens primordium during lens vesicle formation, and demonstrate that this proteoglycan has a speci®c distribution pattern with regard to invagination and fusion processes in the transformation of placode into lens vesicle. More speci®cally, CSPG was detached in: (1) the apical surface of lens epithelial cells, where early CSPG expression was observed in the whole of the lens placode whilst in the vesicle phase it was restricted to the posterior epithelium; (2) intense CSPG expression in the basal lamina, which remained constant for the entire period under study; (3) CSPG expression in the intercellular spaces of the lens primordium epithelium, which increased during the invagination of the primordium and which at the vesicle stage was more evident in the posterior epithelium; and (4) CSPG expression on the edges of the lens placode both prior to and during fusion. Treatment with b-D-xyloside causes signi®cant CSPG depletion in the lens primordium together with severe alterations in the invagination and fusion of the lens vesicle; this leads to the formation of lens primordia which in some cases remain practically¯at or show partial invagination defects or fusion disruption. Similar results were obtained by enzyme digestion with chondroitinase AC but not with type II heparinase, which indicates that alterations induced by b-Dxyloside were due to interference in CSPG synthesis. The ®ndings demonstrate that CSPG is a common component of the lens primordium at the earliest developmental stages during which it undergoes speci®c modi®cations. It also includes experimental evidence to show that`in vivo' CSPG plays an important role in the invagination and fusion processes of the lens primordium.

show abstract

“…It differs in thickness and composition between the anterior and posterior surfaces [65-68]. Additional compositional differences near the germinative zone can be inferred from lectin labeling studies [66]. Zonular fibrils interdigitate into the lens capsule structure in the vicinity of the germinative zone [62,69,70].…”

Section: Discussionmentioning

confidence: 99%

Lens stem cells may reside outside the lens capsule: an hypothesis

Remington

Meyer

2007

Theor Biol Med Model

View full text Add to dashboard Cite

In this paper, we consider the ocular lens in the context of contemporary developments in biological ideas. We attempt to reconcile lens biology with stem cell concepts and a dearth of lens tumors.Historically, the lens has been viewed as a closed system, in which cells at the periphery of the lens epithelium differentiate into fiber cells. Theoretical considerations led us to question whether the intracapsular lens is indeed self-contained. Since stem cells generate tumors and the lens does not naturally develop tumors, we reasoned that lens stem cells may not be present within the capsule. We hypothesize that lens stem cells reside outside the lens capsule, in the nearby ciliary body. Our ideas challenge the existing lens biology paradigm.We begin our discussion with lens background information, in order to describe our lens stem cell hypothesis in the context of published data. Then we present the ciliary body as a possible source for lens stem cells, and conclude by comparing the ocular lens with the corneal epithelium.

show abstract

Developmental Changes in Glycoconjugate Composition During Chick Lens Morphogenesis

Cited by 8 publications

References 0 publications

TGF-β3-Induced Chondroitin Sulphate Proteoglycan Mediates Palatal Shelf Adhesion

TGF-β3-Induced Chondroitin Sulphate Proteoglycan Mediates Palatal Shelf Adhesion

Chondroitin Sulphate Proteoglycan is Involved in Lens Vesicle Morphogenesis in Chick Embryos

Lens stem cells may reside outside the lens capsule: an hypothesis

Contact Info

Product

Resources

About