Putative signaling action of amelogenin utilizes the Wnt/β‐catenin pathway

J. Hard Tissue Biology.

Oka

et al. 2013

Amelogenin is an enamel matrix protein also expressed in periodontal tissues. Recent studies suggest that lysosome-associated membrane proteins (LAMPs) can bind cell surface amelogenin and act as signaling receptors for amelogenin in periodontal ligament (PDL) cells and cementoblasts in vitro. However, whether amelogenin and LAMPs are involved in the development of periodontal tissues is unclear. To address this issue, we used immunohistochemistry to profile LAMPs and amelogenin expression during periodontal tissue development. Paraffin sections from mice at embryonic day 15 (E15) and 1, 2, and 4 weeks were made, and serial sections at each age were stained with hematoxylin-eosin, followed by immunostaining with antiamelogenin, LAMP-1, and LAMP-3. At E15, dental follicle cells, which are the source of periodontal tissues, were amelogenin-positive and weakly positive for LAMP-1 and LAMP-3. At 1 week, dental follicle cells were immunopositive for amelogenin and LAMP-1 but weakly positive for LAMP-3. At 2 weeks, PDL cells were positive for amelogenin and LAMP-1 but negative for LAMP-3. At 4 weeks, PDL cells were immunopositive for both amelogenin and LAMP-1. These results suggest that LAMP-1 is expressed in both the dental follicle and PDL, and that LAMP-1 and LAMP-3 have temporally distinct roles as signaling receptors for amelogenin.

Section: Discussionsupporting

confidence: 83%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Immunohistochemical Study of Lysosome-Associated Membrane Proteins During Periodontal Ligament Development

J. Hard Tissue Biology.

Oka

et al. 2013

“…In this decade, several studies have revealed that amelogenin isoform genes and proteins are expressed not only in enamel formation but also in adult connective tissue forming cells like rat osteoblasts 6) , rat chondrocytes 6) , odontoblasts 7) , cementoblasts 8,9) and periodontal ligament cells 8,10) . In amelogenin null mice, dramatically reduced expression of bone sialoprotein (BSP), a mineralized tissue-specific marker, was observed at both the gene and protein levels 11) .…”

Section: Introductionmentioning

confidence: 99%

Effects of a Chemically Synthesized Leucine-Rich Amelogenin Peptide (csLRAP) on Chondrogenic and Osteogenic Cells

Matsuda

J. Hard Tissue Biology.

Nakashima

et al. 2017

Amelogenin is one of the enamel matrices secreted by ameloblasts and is known to have at least 15 alternative mRNA splicing isoforms. The leucine rich amelogenin peptide (LRAP) is one of most abundant amelogenin isoforms and numerous studies have shown that amelogenin peptides including LRAP, are expressed in cartilage and bone. Lysosome-associated membrane protein-1 (LAMP-1) has been identified as amelogenin binding partner, however, the mechanism of action for LRAP in chondrogenesis or osteogenesis is still unclear. This study aimed to assay the effect of chemically synthesized LRAP (csLRAP) on chondrogenic or osteogenic differentiation with the involvement of LAMP-1. The csLRAP used in this study was generated by F-moc solid phase chemistry based on the mouse LRAP amino acid sequence and was added to the culture medium of the chondrogenic cells, ATDC5 and the osteoblast cells, MC3T3-E1. Both chondrogenic and osteoblast cells, in which an immunopositive reaction to LAMP-1 antibody was observed by immunocytochemistry, showed significant suppression in cell number in the presence of csLRAP at 10 g/ml compared to that in control, but this effect was rescued in the presence of LAMP-1 antibody. On the other hand, the intensity of alcian blue staining in chondrogenic cells and alizarin red staining in osteoblast cells was significantly increased in the presence of csLRAP at a dose of 10 g/ml after 4 weeks culture, and this effect was suppressed in the presence LAMP-1 antibody. Moreover, the chondrogenic or osteogenic differentiation marker genes including Sox9, Type II Collagen, Type X Collagen, Runx2, Alkaline Phosphatase, and Type I Collagen, were upregulated in the presence of csLRAP after one week of culture and were suppressed in the presence of LAMP-1 antibody. These results suggest that csLRAP could promote osteogenic and chondrogenic differentiation in vitro, and that LAMP-1 may be involved in the differentiation and proliferation of these cells.

“…Organic matrices including amelogenin in enamel are almost totally removed during mineralization of enamel before a tooth eruption. Ameloblasts generate at least 14 mRNA alternative splicing isoforms of amelogenin, and these amelogenin genes and proteins are expressed in the cells forming connective tissues like osteoblasts (Haze et al, 2007), chondrocytes (Haze et al), odontoblasts (Oida et al, 2002), cementoblasts (Hatakeyama et al, 2003;Nuñez et al, 2010) and periodontal ligament cells (Matsuzawa et al, 2009) in adult tissues.…”

Section: Introductionmentioning

confidence: 99%

Immunohistochemical Study of Amelogenin and Lysosome-Associate Membrane Proteins (LAMPs) in Cartilage

Oka

et al. 2014

Int. J. Morphol.

SUMMARY:Amelogenin is one of the enamel matrix proteins secreted by ameloblasts during enamel formation in tooth development. Recent studies showed that the amelogenin is expressed in chondrocyte. Lysosome-associated membrane proteins (LAMPs) have been identified as binding partner proteins to amelogenin and it has been suggested they act as signaling receptors of amelogenin. The purpose of this study is to clarify the localization of amelogenin and LAMPs in growth plate cartilage and cartilaginous nodules in micromass culture. Mouse knee joints including tibia growth plate at 4 weeks old and micromass cultures of limb bud mesenchymal cells after 2 weeks were fixed in paraformaldehyde, routinely processed, sections were cut and immunostained with amelogenin, collagen type II and type X, LAMP-1 and -3. The positive immunoreaction of amelogenin was observed both in proliferation and hypertrophic zone cartilage of growth plate after enzymatic pretreatment in immunostaining. Furthermore, cartilaginous nodules in micromass culture were immunopositive to amelogenin. The chondrocytes in the proliferation zone of the growth plate were immunopositive to LAMP-1 but weakly stained in the chondrocytes of hypertrophic zone. These observations indicate that amelogenin may be present in cartilage matrix produced in vivo and in vitro and amelogenin may involve cartilage formation through the LAMP-1 signaling pathway.