Recent advances in developmental and molecular biology during embryogenesis and organogenesis have provided new insights into the mechanism of bone formation. Members of the hedgehog gene family were initially characterized as patterning factors in embryonic development, but recently they have been shown to regulate skeletal formation in vertebrates. The amino terminal fragment of Sonic hedgehog (Shh-N), which is an active domain of Shh, has the ability to induce ectopic cartilage and bone formation in vivo. Shh-N stimulates chondrogenic differentiation in cultures of chondrogenic cell line cells in vitro and inhibits chondrogenesis in primary limb bud cells. These findings suggest that the regulation of chondrogenesis by hedgehog proteins depends on the cell populations being studied. Indian hedgehog (Ihh) is prominently expressed in developing cartilage. Ectopic expression of Ihh decreases type X collagen expression and induces the up-regulation of parathyroid hormone-related peptide (PTHrp) gene expression in perichondrium cells. A negative feedback loop consisting of Ihh and PTHrp, induced by Ihh, appears to regulate the rate of chondrocyte maturation. The direct actions of Shh and Ihh on stimulation of osteoblast differentiation are evidenced by the findings that these factors stimulate alkaline phosphatase activity in cultures of pluripotent mesenchymal cell line cells and osteoblastic cells and that these cells express putative receptors of hedgehog proteins. In conclusion, hedgehog proteins seem to be significantly involved in skeletal formation through multiple actions on chondrogenic mesenchymal cells, chondrocytes, and osteogenic cells.
References
1.
Aikawa T., Shirasuna K., Iwamoto M., Watatani K., Nakamura T., Okura M., et al. (1996). Establishment of bone morphogenetic protein 2 responsive chondrogenic cell line. J Bone Min Res11:544-553.
2.
Akiyama H., Shigeno C., Hiraki Y., Shukunami C., Kohno H., Akagi M., et al. (1997). Cloning of a mouse smoothened cDNA and expression patterns of hedgehog signalling molecules during chondrogenesis and cartilage differentiation in clonal mouse EC cells, ATDC5. Biochem Biophys Res Commun235:142-147.
3.
Alcedo J., Ayzenzon M., Von OT, Noll M., Hooper JE (1996). The Drosophila smoothened gene encodes a seven-pass membrane protein, a putative receptor for the hedgehog signal. Cell86:221-232.
4.
Amizuka N., Warshawsky H., Henderson IE, Goltzman D., Karaplis AC (1994). Parathyroid hormone-related peptide-depleted mice show abnormal epiphyseal cartilage development and altered endochondral bone formation. J Cell Biol126:1611-1623.
5.
Buscher D., Ruther U. (1998). Expression profile of Gli family members and Shh in normal and mutant mouse limb development. Dev Dynam211:88-96.
6.
Chen C., Okayama H. (1987). High-efficiency transformation of mammalian cells by plasmid DNA. Mol Cell Biol7:2745-2752.
7.
Chen Y., Struhl G. (1996). Dual roles for patched in sequestering and transducing Hedgehog. Cell87:553-563.
8.
Chiang C., Litingtung Y., Lee E., Young KE, Corden JL, Westphal H., et al. (1996). Cyclopia and defective axial patterning in mice lacking Sonic hedgehog gene function. Nature383:407-413.
9.
Currie PD, Ingham PW (1996). Induction of a specific muscle cell type by a hedgehog-like protein in zebrafish. Nature382:452-455.
10.
Dahmane N., Lee J., Robins P., Heller P., Ruiz i I Altaba A. (1997). Activation of the transcription factor Gli 1 and the Sonic hedgehog signalling pathway in skin tumours. Nature389:876-881.
11.
Deng C., Wynshaw BA, Zhou F., Kuo A., Leder P. (1996). Fibroblast growth factor receptor 3 is a negative regulator of bone growth. Cell84:911-921.
12.
Echelard Y., Epstein DJ, St-Jacques B., Shen L., Mohler J., McMahon JA, et al. (1993). Sonic hedgehog, a member of a family of putative signaling molecules, is implicated in the regulation of CNS polarity. Cell75:1417-1430.
13.
Ekker SC, Ungar AR, Greenstein P., von Kessler DP, Porter JA, Moon RT, et al. (1995). Patterning activities of vertebrate hedgehog proteins in the developing eye and brain. Curr Biol5:944-955.
14.
Enomoto IM, Iwamoto M., Mukudai Y., Kawakami Y., Nohno T., Higuchi Y., et al. (1998). Bone morphogenetic protein signaling is required for maintenance of differentiated phenotype, control of proliferation, and hypertrophy in chondrocytes. J Cell Biol140:409-418.
15.
Ericson J., Morton S., Kawakami A., Roelink H., Jessell TM (1996). Two critical periods of Sonic Hedgehog signaling required for the specification of motor neuron identity. Cell87:661-673.
16.
Fietz MJ, Concordet J-P., Barbosa R., Johnson R., Krauss S., McMahon AP, et al. (1994). The hedgehog gene family in Drosophila and vertebrate development. Development (Suppl):43-51.
17.
Forbes AJ, Nakano Y., Taylor AM, Ingham PW (1993). Genetic analysis of hedgehog signalling in the Drosophila embryo. Dev (Suppl):115-124.
18.
Gilbert SF (1994). Osteogenesis: the development of bones. In: Developmental biology. Sunderland, MA: Sinauer Associates, Inc., pp. 333-334.
19.
Goodrich LV, Johnson RL, Milenkovic L., McMahon JA, Scott MP (1996). Conservation of the hedgehog/patched signaling pathway from flies to mice: induction of a mouse patched gene by hedgehog. Genes Dev10:301-312.
20.
Hooper JE, Scott MP (1989). The Drosophila patched gene encodes a putative membrane protein required for segmental patterning. Cell59:751-765.
21.
Horton WA (1993). Morphology of connective tissue: cartilage. In: Connective tissue and its heritable disorders. Royce PM, Steinmann B, editors. New York: Wiley-Liss, Inc., pp. 73-84.
22.
Hughes SH, Greenhouse JJ, Petropoulos CJ, Sutrave P. (1987). Adaptor plasmids simplify the insertion of foreign DNA into helper-independent retroviral vectors. J Virol61:3004-3012.
23.
Hui CC, loyner AL (1993). A mouse model of grieg cephalopolysyndactyly syndrome: the extra-toes1 mutation contains an intragenic deletion of the Gli3 gene. Nat Genet3:241-246.
24.
Iwasaki M., Le AX, Helms JA (1997). Expression of indian hedgehog, bone morphogenetic protein 6 and gli during skeletal morphogenesis. Mech Dev69:197-202.
25.
Iwasaki M., Jikko A., Le AX, Helms JA (1998). Direct effects of hedgehog protein on chondrocytes. In: Transactions of the 44th anual meeting, Orthopaedic Research Society, Mar 16-19, 1998, New Orleans, LA, p. 31.
26.
lohnson RL, Laufer E., Riddle RD, Tabin C. (1994). Ectopic expression of Sonic hedgehog alters dorsal-ventral patterning of somites. Cell79:1165-1173.
27.
Johnson RL, Rothman AL, Xie J., Goodrich LV, Bare JW, Bonifas JM, et al. (1996). Human homolog of patched, a candidate gene for the basal cell nevus syndrome. Science272:1668-1671.
28.
Karaplis AC, Luz A., Glowacki J., Bronson RT, Tybulewicz VL, Kronenberg HM, et al. (1994). Lethal skeletal dysplasia from targeted disruption of the parathyroid hormone-related peptide gene. Genes Dev8:277-289.
29.
Kawakami Y., Ishikawa T., Shimabara M., Tanda N., Enomoto-lwamoto M., Iwamoto M., et al. (1996). BMP signaling during bone pattern determination in the developing limb. Development122:3557-3566.
30.
Kinto N., Iwamoto M., Enomoto-lwamoto M., Noji S., Ohuchi H., Kataoka H., et al. (1997). Fibroblasts expressing Sonic hedgehog induce osteoblast differentiation and ectopic bone formation. FEBS Lett404:319-323.
31.
Kinzler KW, Ruppert JM, Bigner SH, Vogelstein B. (1988). The GLI gene is a member of the Kruppel family of zinc finger proteins. Nature332:371-374.
32.
Koike T., Iwamoto M., Shimazu A., Nakashima K., Suzuki F., Kato Y. ( 1990). Potent mitogenic effects of parathyroid hormone (PTH) on embryonic chick and rabbit chondrocytes. Differential effects of age on growth, proteoglycan, and cyclic AMP responses of chondrocytes to PTH. J Clin Invest85:626-631.
33.
Lanske B., Karaplis AC, Lee K., Luz A., Vortkamp A., Pirro A., et al. (1996). PTH/PTHrp receptor in early development and Indian hedgehog-regulated bone growth. Science273:663-666.
34.
Laufer E., Nelson CE, Johnson RL, Morgan BA, Tabin C. (1994). Sonic hedgehog and Fgf-4 act through a signaling cascade and feedback loop to integrate growth and patterning of the developing limb bud. Cell79:993-1003.
35.
Lee JJ, von Kessler DP, Parks S., Beachy PA (1992). Secretion and localized transcription suggest a role in positional signaling for products of the segmentation gene hedgehog. Cell71:33-50.
36.
Lee JJ, Ekker SC, von Kessler DP, Porter JA, Sun BI, Beachy PA (1994). Autoproteolysis in hedgehog protein biogenesis [see comments]. Science266:1528-1537.
37.
Lee J., Platt KA, Censullo P., Ruiz I Altaba A. (1997). Gli1 is a target of Sonic hedgehog that induces ventral neural tube development. Development124:2537-2552.
38.
Lee K., Lanske B., Karaplis AC, Deeds JD, Kohno H., Nissenson RA, et al. (1996). Parathyroid hormone-related peptide delays terminal differentiation of chondrocytes during endochondral bone development. Endocrinology137:5109-5118.
39.
Liem KJ, Tremml G., Roelink H., Jessell TM (1995). Dorsal differentiation of neural plate cells induced by BMPmediated signals from epidermal ectoderm. Cell82:969-979.
40.
Lopez-Martinez A., Chang DT, Chiang C., Porter JA, Ros MA, Simandl BK, et al. (1995). Limb-patterning activity and restricted posterior localization of the amino-terminal product of Sonic hedgehog cleavage. Curr Biol5:791-796.
41.
Marigo V., Tabin C.) (1996). Regulation of Patched by Sonic hedgehog in the developing neural tube. Proc Natl Acad Sci USA93:9346-9351.
42.
Marigo V., Roberts DJ, Lee SM, Tsukurov O, Levi T., Gastier JM, et al. (1995). Cloning, expression, and chromosomal location of SHH and IHH: two human homologues of the Drosophila segment polarity gene hedgehog. Genomics28:44-51.
43.
Marigo V., Johnson RL, Vortkamp A., Tabin CJ (1996a). Sonic hedgehog differentially regulates expression of GLI and GLI3 during development. Dev Biol180:273-283.
44.
Marigo V., Scott MP, Johnson RL, Goodrich LV, Tabin CJ (1996b). Conservation in hedgehog signaling: induction of a chicken patched homolog by Sonic hedgehog in the developing limb. Development122:1225-1233.
45.
Masuya H., Sagai T., Wakana S., Moriwaki K., Shiroishi T. (1995). A duplicated zone of polarizing activity in polydactylous mouse mutants. Genes Dev9:1645-1653.
46.
Masuya H., Sagai T., Moriwaki K., Shiroishi T. (1997). Multigenic control of the localization of the zone of polarizing activity in limb morphogenesis in the mouse. Dev Biol182:42-51.
47.
Mo R., Freer AM, Zinyk DL, Crackower MA, Michaud J., Heng HH, et al. (1997). Specific and redundant functions of Gli2 and Gli3 zinc finger genes in skeletal patterning and development. Development124:113-123.
48.
Murakami S., Nifuji A., Noda M. ( 1997). Expression of Indian hedgehog in osteoblasts and its posttranscriptional regulation by transforming growth factor-beta. Endocrinology138:1972-1978.
49.
Nakamura T., Aikawa T., Iwamoto-Enomoto M., Iwamoto M., Higuchi Y., Pacifici M., et al. (1997). Induction of osteogenic differentiation. Biochem Biophys Res Commun237:465-469.
50.
Niswander L., Jeffrey S., Martin GR, Tickle C. (1994). A positive feedback loop coordinates growth and patterning in the vertebrate limb. Nature371:609-612.
51.
Orenic TV, Slusarski DC, Kroll KL, Holmgren RA (1990). Cloning and characterization of the segment polarity gene cubitus interruptus Dominant of Drosophila. Genes Dev4:1053-1067.
52.
Platt KA, Michaud J., Joyner AL (1997). Expression of the mouse Gli and Ptc genes is adjacent to embryonic sources of hedgehog signals suggesting a conservation of pathways between flies and mice. Mech Dev62:121-135.
53.
Polinkovsky A., Robin NH, Thomas IT, Irons M., Lynn A., Goodman FR, et al. (1997). Mutations in CDMP1 cause autosomal dominant brachydactyly type C [letter]. Nat Genet17:18-19.
54.
Porter JA, von Kessler DP, Ekker SC, Young KE, Lee JJ, Moses K., et al. (1995). The product of hedgehog auto-proteolytic cleavage active in local and long-range signalling. Nature374:363-366.
55.
Riddle RD, Johnson RL, Laufer E., Tabin C. (1993). Sonic hedgehog mediates the polarizing activity of the ZPA. Cell75:1401-1416.
56.
Roelink H., Porter JA, Chiang C., Tanabe Y., Chang DT, Beachy PA, et al. (1995). Floor plate and motor neuron induction by different concentrations of the amino-terminal cleavage product of sonic hedgehog autoproteolysis. Cell81:445-455.
57.
Ruppert JM, Kinzler KW, Wong AJ, Bigner SH, Kao FT, Law ML, et al. (1988). The GLI-Kruppel family of human genes. Mol Cell Biol8:3104-3113.
58.
Ruppert JM, Vogelstein B., Arheden K., Kinzler KW (1990). GLI3 encodes a 190-kilodalton protein with multiple regions of GLI similarity. Mol Cell Biol10:5408-5415.
59.
Schimmang T., Lemaistre M., Vortkamp A., Ruther U. (1992). Expression of the zinc finger gene Gli3 is affected in the morphogenetic mouse mutant extra-toes (Xt). Development116:799-804.
60.
Scott NS, Choung C.-M (1997). Dual action of sonic hedgehog on chondrocyte hypertrophy: retrovirus mediated ectopic sonic hedgehog expression in limb bud micromass culture induces novel cartilage nodules that are positive for alkaline phosphatase and type X collagen. J Cell Sci110:2691-2701.
61.
Stone DM, Hynes M., Armanini M., Swanson TA, Gu Q., Johnson RL, et al. (1996). The tumor-suppressor gene patched encodes a candidate receptor for Sonic hedgehog. Nature384:129-134.
62.
Storm EE, Kingsley DM (1996). Joint patterning defects caused by single and double mutations in members of the bone morphogenetic protein (BMP) family. Development122:3969-3979.
63.
Storm EE, Huynh TV, Copeland NG, Jenkins NA, Kingsley DM, Lee SJ (1994). Limb alterations in brachypodism mice due to mutations in a new member of the TGF beta-superfamily [see comments]. Nature368:639-643.
64.
Su WC, Kitagawa M., Xue N., Xie B., Garofalo S., Cho J., et al. (1997). Activation of Statl by mutant fibroblast growth-factor receptor in thanatophoric dysplasia type II dwarfism. Nature386:288-292.
65.
Tabata T., Eaton S., Kornberg TB (1992). The Drosophila hedgehog gene is expressed specifically in posterior compartment cells and is a target of engrailed regulation. Genes Dev6:2635-2645.
66.
Tabin C. (1995). The initiation of the limb bud: growth factors, Hox genes and retinoids. Cell80:671-674.
67.
Takigawa M., Ishida H., Takano T., Suzuki F. (1980). Polyamine and differentiation: induction of ornithine decarboxylase by parathyroid hormone is a good marker of differentiated chondrocytes. Proc Natl Acad Sci USA77:1481-1485.
68.
Tanabe Y., Roelink H., Jessell TM (1995). Induction of motor neurons by Sonic hedgehog is independent of floor plate differentiation. Curr Biol5:651-658.
69.
Tashiro S., Michiue T., Higashijima S., Zenno S., Ishimaru S., Takahashi F., et al. (1993). Structure and expression of hedgehog, a Drosophila segment-polarity gene required for cell-cell communication. Gene124:183-189.
70.
Thien H., Buscher D., Ruther U. (1996). Cloning and sequence analysis of the murine Gli3 cDNA. Biochim Biophys Acta1307:267-269.
71.
Thomas JT, Kilpatrick MW, Lin K., Erlacher L., Lembessis P., Costa T., et al. (1997). Disruption of human limb morphogenesis by a dominant negative mutation in CDMP1. Nat Genet17:58-64.
72.
Vortkamp A., Lee K., Lanske B., Segre GV, Kronenberg HM, Tabin CJ (1996). Regulation of rate of cartilage differentiation by Indian hedgehog and PTH-related protein. Science273:613-622.
73.
Vortkamp A., Pathi S., Peretti GM, Caruso EM, Zaleske DJ, Tabin CJ (1998). Recapitulation of signals regulating embryonic bone formation during postnatal growth and in fracture repair. Mech Dev71:65-76.
74.
Wachler F., Christ B., Jacob HJ (1981). On the determination of mesodermal tissues in the avian embryonic wing bud. Anat Embryol161:283-289.
75.
Zou H., Wieser R., Massague J., Niswander L. (1997). Distinct roles of type I bone morphogenetic protein receptors in the formation and differentiation of cartilage. Genes Dev11:2191-2203.
