The highly modified membrane of cornified cells in stratified squamous epithelia: A comparison of heterogenous deposits in keratinized and nonkeratinized epithelia

Nakano, Shunji; Fukuyama, Kimie; Epstein, William L.

doi:10.1007/bf00215516

Cited by 6 publications

(3 citation statements)

References 24 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Keratohyalin has two functions: the integration of keratin filaments to form keratin and the formation of a cell envelope with the help of the enzyme transglutaminase [Nakano et al,1987;Reibel et al, 1989]. Within the keratohyalin granules the two proteins filaggrin and loricrin have been identified and both seem to be needed for the above-mentioned processes.…”

Section: Discussionmentioning

confidence: 99%

Changes in the Epithelium of the Vaginal Complex during the Estrous Cycle of the Marsupial <i>Monodelphis domestica</i>

Regli

Kress²

2002

Cells Tissues Organs

View full text Add to dashboard Cite

The vaginal complex of marsupials differs from that of eutherians. Cervices open separately in a sinus vaginalis or cul-de-sac. Two lateral vaginae adjoin the sinus vaginalis and fuse at the level of the urethra opening and form the sinus urogenitalis. During the estrous cycle the vaginal epithelium undergoes a number of specified morphological changes. This paper is the first to describe these changes on an ultrastructural level in a marsupial. Investigations in Monodelphis vagina reveal that a cyclic switch exists between a keratinized and a stratified nonkeratinized epithelium. Keratinization starts during proestrus and reaches its maximum during estrus. In the postestrus, desquamation of the stratum corneum takes place, mostly in two steps. In metestrus one to two additional layers of the now nonkeratinized surface cells are shed into the vaginal lumen. Typical cell structures, such as keratin filaments, keratohyalin and membrane-coating granules, are involved in the keratinization process. Keratohyalin is found in the cytoplasm as well as in the nucleus of stratum granulosum cells, a phenomenon which is known from other parakeratinized epithelia of rapid turnover. Membrane-coating granules, responsible for the permeability barrier between the epithelial cells, are of the nonlamellated type in the nonkeratinized epithelium and produce an amorphous material in the intercellular spaces after extrusion. At periods, however, when the epithelium is keratinized, membrane-coating granules are of the lamellated type and form a lamellated barrier structure after extrusion in the intercellular space. The loss of the protective keratinized layers asks for an additional defense mechanism for the epithelium. The migration of leukocytes through the epithelium predominantly during post- and metestrus and their presence in the vaginal lumen may play a protective role together with the bacterial content.

show abstract

Section: Discussionmentioning

confidence: 99%

Changes in the Epithelium of the Vaginal Complex during the Estrous Cycle of the Marsupial <i>Monodelphis domestica</i>

Regli

Kress²

2002

Cells Tissues Organs

View full text Add to dashboard Cite

show abstract

“…Both hINV and type I transglutaminase, the enzyme responsible for covalent cross-link formation in surface epithelia, are expressed in corneal epithelial cells and covalently cross-linked structure is likely to play a role during the normal corneal epithelial cell life cycle 12,13,16 and during corneal wound healing. [22][23][24] Thus, it is important to understand this regulation.…”

Section: Discussionmentioning

confidence: 99%

“…12,13,16 Indeed, transglutaminase activity acts to stabilize corneal tissue, and increased transglutaminase activity is detected in corneal wounds. [22][23][24] hINV expression has been reported to be regulated by activator protein one (AP1) and lens epithelium-derived growth factor in SV40-immortalized human corneal epithelial cells 25,26 ; however, many fundamental questions regarding expression remain to be addressed. In the present study we show that a specific AP1 transcription factor-binding site is required for hINV expression in differentiating normal human corneal epithelial cells.…”

mentioning

confidence: 99%

An Involucrin Promoter AP1 Transcription Factor Binding Site Is Required for Expression of Involucrin in the Corneal Epithelium In Vivo

Adhikary¹,

Crish²,

Bone³

et al. 2005

Invest. Ophthalmol. Vis. Sci.

View full text Add to dashboard Cite

PURPOSE. Cell division of corneal limbal stem cells gives rise to transient amplifying cells that ultimately differentiate to form the multilayered corneal epithelium. The mechanisms that regulate changes in gene expression during this process are not well understood. In the present study, the involucrin gene was used as a model to study this regulation. METHODS. Regulation of human involucrin gene expression and promoter activity was assessed using in vivo transgenic mouse models and cultured primary human corneal epithelial cells. RESULTS. Human involucrin (hINV) is a structural protein that is selectively expressed in differentiating corneal epithelial cells. The results reveal that an activator protein one (AP1) DNAbinding site is essential for appropriate basal and stimulusdependent hINV promoter activity. Mutation of this site, AP1-5, results in a loss of hINV gene expression in the corneal epithelium in vivo and in cultured corneal epithelial cells. A gel mobility supershift analysis revealed interaction of the AP1 factors, Fra-1 and JunB, with this element. Inhibition of AP1 function with a dominant-negative form of AP1 also inhibited expression. Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA), a protein kinase C activator, increased hINV gene expression, a response that correlates with increased AP1 factor (Fra-1 and JunB) binding to the hINV gene AP1-5 response element. CONCLUSIONS. These findings point to an essential role for AP1 transcription factors, acting through a distal regulatory region AP1-5 element, in the regulation of involucrin gene expression during corneal epithelial cell differentiation. (Invest Ophthalmol Vis Sci.

show abstract

Keratinization of middle ear cholesteatomas

Broekaert

Pattin

Coucke

et al. 1990

Eur Arch Otorhinolaryngol

View full text Add to dashboard Cite

A histochemical study was performed to determine the involvement of epidermal transglutaminase (ETgase) in the keratinization of middle ear cholesteatomatous lesions, and to compare it with its role in the middle ear mucosa and epidermis. In a first assay, we localized the (E)Tgase activity in situ. A second immunohistochemical assay revealed the distribution of the particulate form of ETgase, which is involved in cross-linked envelope formation. A remarkable difference between strongly keratinized epidermal tissues and the cholesteatoma matrix is the frequent observation in the latter of the remnants of (E)Tgase activity in cytosol, even in advanced stages of differentiation. As a consequence, the cell-membrane-associated ETgase activity, and thus the extent of cross-linking within the envelope, is at a lower level than expected. This aspect is reminiscent of the keratinization phenomenon manifested by thin epidermal tissues. In addition, our findings are the first to show that ETgase is a substantial marker of middle ear mucosa.

show abstract

The highly modified membrane of cornified cells in stratified squamous epithelia: A comparison of heterogenous deposits in keratinized and nonkeratinized epithelia

Cited by 6 publications

References 24 publications

Changes in the Epithelium of the Vaginal Complex during the Estrous Cycle of the Marsupial <i>Monodelphis domestica</i>

Changes in the Epithelium of the Vaginal Complex during the Estrous Cycle of the Marsupial <i>Monodelphis domestica</i>

An Involucrin Promoter AP1 Transcription Factor Binding Site Is Required for Expression of Involucrin in the Corneal Epithelium In Vivo

Keratinization of middle ear cholesteatomas

Contact Info

Product

Resources

About