The time-dependent rearrangement of the epithelial basement membrane in human skin wounds

In 62 human skin wounds (surgical wounds, stab wounds and lacerations after surgical treatment) we analyzed the immunohistochemical localization of collagen IV in the epithelial basement membrane. In 27 of these wounds the distribution of collagen VII, which represents a specific component of the basement membrane of stratified epithelia, was also analyzed. We were able to demonstrate a virtually identical co-distribution of both collagen IV and VII in the wound area with no significant time-dependent differences in the appearance of both collagen types. Fragments of the epithelial basement membrane could be detected in the wound area from as early as 4 days after wounding and after 8 days a complete restitution of the epithelial basement membrane was observed. In all cases with a wound age of more than 21 days the basement membrane was completely reformed over the former lesional area. The period between 8 and 21 days after wounding was characterized by a wide variability ranging from complete restitution to deposition of basement membrane fragments or total lack of the epidermal basement membrane

J Biol Chem

Collagen XXIII is a member of the transmembranous subfamily of collagens containing a cytoplasmic domain, a membrane-spanning hydrophobic domain, and three extracellular triple helical collagenous domains interspersed with non-collagenous domains. We cloned mouse, chicken, and human{alpha}1(XXIII) collagen cDNAs and showed that this non-abundant collagen has a limited tissue distribution in non-tumor tissues. Lung, cornea, brain, skin, tendon, and kidney are the major sites of expression. In contrast, five transformed cell lines were tested for collagen XXIII expression, and all expressed the mRNA. In vivo the {alpha}1(XXIII) mRNA is found in mature and developing organs, the latter demonstrated using stages of embryonic chick cornea and mouse embryos. Polyclonal antibodies were generated in guinea pig and rabbit and showed that collagen XXIII has a transmembranous form and a shed form. Comparison of collagen XXIII with its closest relatives in the transmembranous subfamily of collagens, types XIII and XXV, which have the same number of triple helical and non-collagenous regions, showed that there is a discontinuity in the alignment of domains but that striking similarities remain despite this

(5S,6S)-4,5-Dimethyl-3-methyl­acryloyl-6-phenyl-1,3,4-oxadiazinan-2-one

The title compound, C15H18N2O3, is an example of an oxadiazinan-2-one with significant inter­action between the N3-acyl and N4-methyl groups. These steric inter­actions result in a large torsion angle between the two carbonyl groups, not present with acyl substituents with less steric demand

Human amnion contains a novel laminin variant, laminin 7, which like laminin 6, covalently associates with laminin 5 to promote stable epithelial-stromal attachment.

International audienceStable attachment of external epithelia to the basement membrane and underlying stroma is mediated by transmembrane proteins such as the integrin alpha6beta4 and bullous pemphigoid antigen 2 within the hemidesmosomes along the basolateral surface of the epithelial cell and their ligands that include a specialized subfamily of laminins. The laminin 5 molecule (previously termed kalinin/nicein/epiligrin) is a member of this epithelial-specific subfamily. Laminin 5 chains are not only considerably truncated within domains III-VI, but are also extensively proteolytically processed in vitro and in vivo. As a result, the domains expected to be required for the association of laminins with other basement membrane components are lacking in the mature laminin 5 molecule. Therefore, the tight binding of laminin 5 to the basement membrane may occur by a unique mechanism. To examine laminin 5 in tissue, we chose human amnion as the source, because of its availability and the similarity of the amniotic epithelial basement membrane with that of skin. We isolated the laminin 5 contained within the basement membrane of human amnion. In addition to monomeric laminin 5, we find that much of the laminin 5 isolated is covalently adducted with laminin 6 (alpha3beta1gamma1) and a novel laminin isotype we have termed laminin 7 (alpha3beta2gamma1). We propose that the association between laminin 5 and laminins 6 and 7 is a mechanism used in amnion to allow stable association of laminin 5 with the basement membrane. The beta2 chain is seen at the human amniotic epithelial-stromal interface and at the dermal-epidermal junction of fetal and adult bovine skin by immunofluorescence, but is not present, or only weakly present, in neonatal human skin.Stable attachment of external epithelia to the basement membrane and underlying stroma is mediated by transmembrane proteins such as the integrin alpha6beta4 and bullous pemphigoid antigen 2 within the hemidesmosomes along the basolateral surface of the epithelial cell and their ligands that include a specialized subfamily of laminins. The laminin 5 molecule (previously termed kalinin/nicein/epiligrin) is a member of this epithelial-specific subfamily. Laminin 5 chains are not only considerably truncated within domains III-VI, but are also extensively proteolytically processed in vitro and in vivo. As a result, the domains expected to be required for the association of laminins with other basement membrane components are lacking in the mature laminin 5 molecule. Therefore, the tight binding of laminin 5 to the basement membrane may occur by a unique mechanism. To examine laminin 5 in tissue, we chose human amnion as the source, because of its availability and the similarity of the amniotic epithelial basement membrane with that of skin. We isolated the laminin 5 contained within the basement membrane of human amnion. In addition to monomeric laminin 5, we find that much of the laminin 5 isolated is covalently adducted with laminin 6 (alpha3beta1gamma1) and a novel laminin isotype we have termed laminin 7 (alpha3beta2gamma1). We propose that the association between laminin 5 and laminins 6 and 7 is a mechanism used in amnion to allow stable association of laminin 5 with the basement membrane. The beta2 chain is seen at the human amniotic epithelial-stromal interface and at the dermal-epidermal junction of fetal and adult bovine skin by immunofluorescence, but is not present, or only weakly present, in neonatal human skin

(5S)-4-(2,2-Dimethyl­prop­yl)-5-isopropyl-1,3,4-oxadiazinan-2-one

The title compound, C11H22N2O2, has one chiral center and packs in the monoclinic space group P21. The asymmetric unit has five crystallographically independent mol­ecules, four of which engage in inter­molecular N—H⋯O hydrogen bonding

(5S,6R)-5-Methyl-6-phenyl-4-propyl-1,3,4-oxadiazinane-2-thione

The title mol­ecule, C13H18N2OS, is an oxadiazinanthione derived from (1R,2S)-norephedrine. There are two molecules in the asymmetric. Both adopt roughly half-chair conformations; however, the 5-position carbon orients out of opposite faces of the oxadiazinanthiones plane in the two molecules. In the crystal structure, they are oriented as a dimer linked by a pair of N—H⋯S hydrogen bonds. The absolute configuration has been established from anomalous dispersion and confirms the known stereochemistry based on the synthetic procedure

Laminin database: a tool to retrieve high-throughput and curated data for studies on laminins

The Laminin(LM)-database, hosted at http://www.lm.lncc.br, is the first database focusing a non-collagenous extracellular matrix protein family, the LMs. Part of the knowledge available in this website is automatically retrieved, whereas a significant amount of information is curated and annotated, thus placing LM-database beyond a simple repository of data. In its home page, an overview of the rationale for the database is seen and readers can access a tutorial to facilitate navigation in the website, which in turn is presented with tabs subdivided into LMs, receptors, extracellular binding and other related proteins. Each tab opens into a given LM or LM-related molecule, where the reader finds a series of further tabs for ‘protein’, ‘gene structure’, ‘gene expression’ and ‘tissue distribution’ and ‘therapy’. Data are separated as a function of species, comprising Homo sapiens, Mus musculus and Rattus novergicus. Furthermore, there is specific tab displaying the LM nomenclatures. In another tab, a direct link to PubMed, which can be then consulted in a specific way, in terms of the biological functions of each molecule, knockout animals and genetic diseases, immune response and lymphomas/leukemias. LM-database will hopefully be a relevant tool for retrieving information concerning LMs in health and disease, particularly regarding the hemopoietic system