Expression and localization of laminin 5, laminin 10, type IV collagen, and amelotin in adult murine gingiva

Abstract

The biochemical composition of the internal and external basal laminae in the junctional epithelium differs significantly, and the precise cellular origin of their respective molecules remains to be determined. In the present study, the expression and localization of three basement membrane-specific molecules-laminin 5 (γ2 chain), type IV collagen (α1 chain), and laminin 10 (α5 chain)-and one tooth-specific molecule, amelotin, was analyzed in adult murine gingiva by using in situ hybridization and immunohistochemistry. The results showed that the outermost cells in junctional epithelium facing the tooth enamel strongly expressed laminin 5 mRNA, supporting the immunohistochemical staining data. This suggests that laminin 5 is actively synthesized in junctional epithelial cells and that the products are incorporated into the internal basal lamina to maintain firm epithelial adhesion to the tooth enamel throughout life. Conversely, no amelotin mRNA signals were detected in the junctional epithelial cells, suggesting that the molecules localized on the internal basal lamina are mainly derived from maturation-stage ameloblasts. Weak and sporadic expression of type IV collagen in addition to laminin 10 in the gingiva indicates that these molecules undergo turnover less frequently in adult animals.

Proinflammatory cytokines induce amelotin transcription in human gingival fibroblasts

“…It remains to be demonstrated whether AMTN is transcribed and secreted by gingival connective tissue cells or by cells of the gingival epithelium. In any event, the transcription level of AMTN has been found to be too low for detection by in situ hybridization (8,25), and therefore this issue remains beyond the scope of the present study.…”

Inactivation of the Odontogenic ameloblast-associated gene affects the integrity of the junctional epithelium and gingival healing

“…The difference in outcome at the level of the JE between Odam and Amtn KO may reflect the fact that ODAM is not only found at cell-tooth interfaces but is also continuously present among the cells of the JE. Indeed, AMTN may only be transiently expressed in the JE (Sawada et al, 2014) and actually appears late during JE regeneration (Nishio et al, 2010). Like other MPs (Roberts, 2011), it would be expected that the activity of ODAM is contextual, which would explain the increase in severity of the JE phenotype with age in the KO and delay in regeneration following gingivectomy.…”

Ultrastructural immunolocalization of laminin 332 (laminin 5) at dento-gingival interface in Macaca fuscata monkey

“…An earlier series of immunohistochemical experiments revealed that the internal basal lamina contains laminin 332 [13,[15][16][17][18][19], but no other basement membrane-specific molecules such as type IV collagen [15,[23][24][25], laminin 1/10 [15,19], perlecan [19], or nidogen [15]. At the ultrastructural level using immunoperoxidase labeling, Atsuta et al [20] demonstrated laminin 332 on the internal basal lamina (mainly on the lamina densa and scantly on the lamina lucida) in rat molar gingiva.…”

“…ab14509; dilution 1:100; Abcam, Cambridge, UK), overnight at 4°C in a moist chamber. This antibody has been shown to exhibit cross-reactivity with non-human animal tissue [17,18]. In the negative controls, the primary antibody was replaced with PBS.…”

“…Recent immunohistochemical studies have demonstrated that only laminin 332 (formerly laminin 5), an extracellular matrix involved in cell adhesion and migration, was localized at the dento-gingival border in rodent [13][14][15][16][17][18] or human tooth [19]. Using a horse radish peroxidase-labeled antibody, Atsuta et al [20] demonstrated the ultrastructural distribution of laminin 5 (c2 chain) in the internal basal lamina of junctional epithelium in rat molars.…”