Drug – bio-affecting and body treating compositions – Designated organic active ingredient containing – Having -c- – wherein x is chalcogen – bonded directly to...
Reexamination Certificate
1998-06-04
2002-08-13
Badio, Barbara P. (Department: 1616)
Drug, bio-affecting and body treating compositions
Designated organic active ingredient containing
Having -c-, wherein x is chalcogen, bonded directly to...
Reexamination Certificate
active
06432970
ABSTRACT:
BACKGROUND OF THE INVENTION
Pattern formation is the activity by which embryonic cells form ordered spatial arrangements of differentiated tissues. The physical complexity of higher organisms arises during embryogenesis through the interplay of cell-intrinsic lineage and cell-extrinsic signaling. Inductive interactions are essential to embryonic patterning in vertebrate development from the earliest establishment of the body plan, to the patterning of the organ systems, to the generation of diverse cell types during tissue differentiation (Davidson, E., (1990)
Development
108: 365-389; Gurdon, J. B., (1992)
Cell
68: 185-199; Jessell, T. M. et al., (1992)
Cell
68: 257-270). The effects of developmental cell interactions are varied. Typically, responding cells are diverted from one route of cell differentiation to another by inducing cells that differ from both the uninduced and induced states of the responding cells (inductions). Sometimes cells induce their neighbors to differentiate like themselves (homeogenetic induction); in other cases a cell inhibits its neighbors from differentiating like itself. Cell interactions in early development may be sequential, such that an initial induction between two cell types leads to a progressive amplification of diversity. Moreover, inductive interactions occur not only in embryos, but in adult cells as well, and can act to establish and maintain morphogenetic patterns as well as induce differentiation (J. B. Gurdon (1992)
Cell
68:185-199).
Members of the Hedgehog family of signaling molecules mediate many important short- and long-range patterning processes during invertebrate and vertebrate development. In the fly a single hedgehog gene regulates segmental and imaginal disc patterning. In contrast, in vertebrates a hedgehog gene family is involved in the control of left-right asymmetry, polarity in the CNS, somites and limb, organogenesis, chondrogenesis and spermatogenesis.
The first hedgehog gene was identified by a genetic screen in the fruitfly
Drosophila melanogaster
(Nüsslein-Volhard, C. and Wieschaus, E. (1980)
Nature
287, 795-801). This screen identified a number of mutations affecting embryonic and larval development. In 1992 and 1993, the molecular nature of the
Drosophila hedgehog
(hh) gene was reported (C. F., Lee et al. (1992)
Cell
71, 33-50), and since then, several hedgehog homologues have been isolated from various vertebrate species. While only one hedgehog gene has been found in Drosophila and other invertebrates, multiple Hedgehog genes are present in vertebrates.
The various Hedgehog proteins consist of a signal peptide, a highly conserved N-terminal region, and a more divergent C-terminal domain. In addition to signal sequence cleavage in the secretory pathway (Lee, J. J. et al. (1992)
Cell
71:33-50; Tabata, T. et al. (1992)
Genes Dev.
2635-2645: Chang, D. E. et al. (1994)
Development
120:3339-3353), Hedgehog precursor proteins undergo an internal autoproteolytic cleavage which depends on conserved sequences in the C-terminal portion (Lee et al. (1994)
Science
266:1528-1537; Porter et al. (1995)
Nature
374:363-366). This autocleavage leads to a 19 kD N-terminal peptide and a C-terminal peptide of 26-28 kD (Lee et al. (1992) supra; Tabata et al. (1992) supra; Chang et al. (1994) supra; Lee et al. (1994) supra; Bumcrot, D. A., et al (1995)
Mol. Cell. Biol.
15:2294-2303; Porter et al. (1995) supra; Ekker, S. C. et al. (1995)
Curr. Biol.
5:944-955; Lai, C. J. et al. (1995)
Development
121:2349-2360). The N-terminal peptide stays tightly associated with the surface of cells in which it was synthesized, while the C-terminal peptide is freely diffusible both in vitro and in vivo (Porter et al. (1995)
Nature
374:363; Lee et al. (1994) supra; Bumcrot et al. (1995) supra; Mart', E. et al. (1995)
Development
121:2537-2547; Roelink, H. et al. (1995)
Cell
81:445-455). Interestingly, cell surface retention of the N-terminal peptide is dependent on autocleavage, as a truncated form of HH encoded by an RNA which terminates precisely at the normal position of internal cleavage is diffusible in vitro (Porter et al. (1995) supra) and in vivo (Porter, J. A. et al. (1996)
Cell
86, 21-34). Biochemical studies have shown that the autoproteolytic cleavage of the HH precursor protein proceeds through an internal thioester intermediate which subsequently is cleaved in a nucleophilic substitution. It is likely that the nucleophile is a small lipophilic molecule which becomes covalently bound to the C-terminal end of the N-peptide (Porter et al. (1996) supra), tethering it to the cell surface. The biological implications are profound. As a result of the tethering, a high local concentration of N-terminal Hedgehog peptide is generated on the surface of the Hedgehog producing cells. It is this N-terminal peptide which is both necessary and sufficient for short and long range Hedgehog signaling activities in Drosophila and vertebrates (Porter et al. (1995) supra; Ekker et al. (1995) supra; Lai et al (1995) supra; Roelink, H. et al. (1995)
Cell
81:445-455; Porter et al. (1996) supra; Fietz, M. J. et al. (1995)
Curr. Biol.
5:643-651; Fan, C. -M. et al. (1995)
Cell
81:457-465; Mart', E., et al. (1995)
Nature
375:322-325; Lopez-Martinez et al. (1995)
Curr. Biol
5:791-795: Ekker, S. C. et al. (1995)
Development
121:2337-2347; Forbes, A. J. et al.(1996)
Development
122:1125-1135).
HH has been implicated in short- and longe range patterning processes at various sites during Drosophila development. In the establishment of segment polarity in early embryos, it has short range effects which appear to be directly mediated, while in the patterning of the imaginal discs, it induces long range effects via the induction of secondary signals.
In vertebrates, several hedgehog genes have been cloned in the past few years. Of these genes, Shh has received most of the experimental attention, as it is expressed in different organizing centers which are the sources of signals that pattern neighbouring tissues. Recent evidence indicates that Shh is involved in these interactions.
The expression of Shh starts shortly after the onset of gastrulation in the presumptive midline mesoderm, the node in the mouse (Chang et al. (1994) supra; Echelard, Y. et al. (1993)
Cell
75:1417-1430), the rat (Roelink, H. et al. (1994)
Cell
76:761-775) and the chick (Riddle, R. D. et al. (1993)
Cell
75:1401-1416), and the shield in the zebrafish (Ekker et al. (1995) supra; Krauss, S. et al. (993)
Cell
75:1431-1444). In chick embyros, the Shh expression pattern in the node develops a left-right asymmetry, which appears to be responsible for the left-right situs of the heart (Levin, M. et al. (1995)
Cell
82:803-814).
In the CNS, Shh from the notochord and the floorplate appears to induce ventral cell fates. When ectopically expressed, Shh leads to a ventralization of large regions of the mid- and hindbrain in mouse (Echelard et al. (1993) supra; Goodrich, L. V. et al. (1996)
Genes Dev.
10:301-312), Xenopus (Roelink, H. et al. (1994) supra; Ruiz i Altaba, A. et al. (1995)
Mol. Cell. Neurosci.
6:106-121), and zebrafish (Ekker et al. (1995) supra; Krauss et al. (1993) supra; Hammerschmidt, M., et al. (1996)
Genes Dev.
10:647-658). In explants of intermediate neuroectoderm at spinal cord levels, Shh protein induces floorplate and motor neuron development with distinct concentration thresholds, floor plate at high and motor neurons at lower concentrations (Roelink et al. (1995) supra; Mart' et al. (1995) supra; Tanabe, Y. et al. (1995)
Curr. Biol.
5:651-658). Moreover, antibody blocking suggests that Shh produced by the notochord is required for notochord mediated induction of motor neuron fates (Mart' et al. (1995) supra). Thus, high concentration of Shh on the surface of Shh-producing midline cells appears to account for the contact-mediated induction of Doorplate observed in vitro (Placzek, M. et al. (1993)
Development
117:205-218), and the midline positioning of the floorplate immediately above the n
Beachy Philip A.
Cooper Michael K.
Porter Jeffrey A.
Badio Barbara P.
Halstead David P.
Johns Hopkins University School of Medicine
Ropes & Gray
Vincent Matthew P.
LandOfFree
Inhibitors of hedgehog signaling pathways, compositions and... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Inhibitors of hedgehog signaling pathways, compositions and..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Inhibitors of hedgehog signaling pathways, compositions and... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2919428