Differential effect of amelogenin peptides on osteogenic differentiation in vitro: identification of possible new drugs for bone repair and regeneration.
Enamel matrix proteins (EMP) have been shown to promote regeneration of periodontal ligament and root cementum, and sometimes to enhance the differentiation of bone-forming cells in vitro and new bone growth in vivo. However, the inconsistent and unpredictable effects of EMP that have been reported for bone regeneration may be due to the highly variable composition of this heterogeneous material, which is comprised mainly of amelogenin and amelogenin-derived peptides. The present study has therefore examined the effects of naturally occurring low-molecular-weight (LMW) and high-molecular-weight (HMW) fractions of Emdogain(®) (EMD; Institut Straumann, Basel, Switzerland), a commercially available form of EMP, on osteogenic differentiation of bone precursor cells in vitro. In addition, the effects of chemically synthesized specific components of LMW and HMW-namely, the tyrosine-rich amelogenin peptide (TRAP), a specific amelogenin isoform derived by proteolytic clipping, and a leucine-rich amelogenin peptide (LRAP), an isoform derived by alternative splicing-on bone-forming cell activity were also investigated. Our findings demonstrate that while TRAP suppressed the formation of bone-like mineralized nodules, LRAP upregulated osteogenic differentiation. Furthermore, synthetically produced TRAP and its unique C-terminal 12 amino acid sequence (TCT) also suppressed bone-forming cells, whereas LRAP and its unique C-terminal 23 amino acid sequence (LCT) markedly enhanced terminal differentiation of bone-forming cells. These findings suggest that the differential effects of amelogenin-derived peptide sequences present in EMP could be of potential clinical value, with the novel bioactive TCT peptide as a useful tool for limiting pathological bone cell growth and the unique LCT sequence having therapeutic benefits in the treatment of periodontal and orthopedic diseases.
Periodontology Unit, Department of Clinical Research, University College London, London, United Kingdom.
Harsh D
HD
Amin
Irwin
I
Olsen
Jonathan C
JC
Knowles
Nikolaos
N
Donos
D000328:Adult; D053523:Amelogenin / Q000737:chemistry / Q000494:pharmacology*; D000595:Amino Acid Sequence; D015415:Biomarkers / Q000378:metabolism; D001861:Bone Regeneration / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects / Q000473:pathology*; D002113:Calcification, Physiologic / Q000187:drug effects; D002352:Carrier Proteins / Q000494:pharmacology; D002454:Cell Differentiation / Q000187:drug effects*; D005591:Chemical Fractionation; D003746:Dental Enamel Proteins / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010011:Osteocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D010455:Peptides / Q000494:pharmacology*; D010513:Periodontal Ligament / Q000166:cytology; D020033:Protein Isoforms / Q000737:chemistry / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D051785:Smad Proteins / Q000378:metabolism; D014945:Wound Healing / Q000187:drug effects*; D000099176:Noggin Protein
D053523:Amelogenin; D015415:Biomarkers; D002352:Carrier Proteins; D003746:Dental Enamel Proteins; D010455:Peptides; D020033:Protein Isoforms; D051785:Smad Proteins; D000099176:Noggin Protein; C109069:enamel matrix proteins