The synergistic induction of bone formation by the osteogenic proteins of the TGF-β supergene family

• Published in: Biomaterials 2016-10, Vol.104, p.279-296
• Main Authors: Ripamonti, Ugo, Parak, Ruqayya, Klar, Roland M, Dickens, Caroline, Dix-Peek, Thérèse, Duarte, Raquel
• Format: Article
• Language: English
• Subjects: Advanced Basic Science; Animals; Bone Development - physiology; Bone morphogenetic protein-7; Bone Regeneration - physiology; Dentistry; Dogs; Humans; Multigene Family - physiology; Noggin; Osteogenesis - physiology; Osteogenic protein-1; Primates; Species Specificity; TGF-beta Superfamily Proteins - metabolism; Transforming growth factor-β1; Transforming growth factor-β3
• ISSN: 0142-9612; 1878-5905
• DOI: 10.1016/j.biomaterials.2016.07.018

Abstract The momentum to compose this Leading Opinion on the synergistic induction of bone formation suddenly arose when a simple question was formulated during a discussion session on how to boost the often limited induction of bone formation seen in clinical contexts. Re-examination of morphological and molecular data available on the rapid induction of bone formation by the recombinant human transforming growth factor-β3 (hTGF-β3 ) shows that hTGF-β3 replicates the synergistic induction of bone formation as invocated by binary applications of hOP-1:hTGF-β1 at 20:1 by weight when implanted in heterotopic sites of the rectus abdominis muscle of the Chacma baboon, Papio ursinus . The rapid induction of bone formation in primates by hTGF-β3 may stem from bursts of cladistic evolution, now redundant in lower animal species but still activated in primates by relatively high doses of hTGF-β3 . Contrary to rodents, lagomorphs and canines, the three mammalian TGF-β isoforms induce rapid and substantial bone formation when implanted in heterotopic rectus abdominis muscle sites of P. ursinus , with unprecedented regeneration of full thickness mandibular defects with rapid mineralization and corticalization. Provocatively, thus providing potential molecular and biological rationales for the apparent redundancy of osteogenic molecular signals in primates, binary applications of recombinant human osteogenic protein-1 (hOP-1) with low doses of hTGF-β1 and -β3 , synergize to induce massive ossicles in heterotopic rectus abdominis , orthotopic calvarial and mandibular sites of P. ursinus. The synergistic binary application of homologous but molecularly different soluble molecular signals has indicated that per force several secreted molecular signals are required singly, synchronously and synergistically to induce optimal osteogenesis. The morphological hallmark of the synergistic induction of bone formation is the rapid differentiation of large osteoid seams enveloping haematopoietic bone marrow that forms by day 15 in heterotopic rectus abdominis sites. Synergistic binary applications also induce the morphogenesis of rudimentary embryonic growth plates indicating that the “memory” of developmental events in embryo can be redeployed postnatally by the application of morphogen combinations. Synergistic binary applications or single relatively high doses of hTGF-β3 have shown that hTGF-β3 induces bone by expressing a variety of inductive morphogenetic proteins that resul