Pan-neurotrophin 1: a genetically engineered neurotrophic factor displaying multiple specificities in peripheral neurons in vitro and in vivo.
Pan-neurotrophin 1 (PNT-1) is a synthetic trophic factor engineered by combining active domains of the neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), and neurotrophin 3 (NT-3) into an NT-3 backbone. This molecule was produced in transiently transfected COS cells or in baculovirus-infected insect cells transfected COS cells or in baculovirus-infected insect cells and subsequently purified to homogeneity. Saturation binding in embryonic spinal sensory neurons demonstrated a greater number of high-affinity binding sites for PNT-1 than for its parental molecule NT-3. PNT-1 was shown to efficiently block the chemical crosslinking of NGF, BDNF, and NT-3 to their cognate Trk receptors and to the low-affintiy NGF receptor expressed on neuronal and nonneuronal cells. PNT-1 stimulated survival and proliferation of MG87 fibroblasts expressing either TrkA, TrkB, or TrkC. PNT-1 also promoted survival of a greater number of embryonic dorsal root ganglion neurons than any of the other neurotrophins alone, and its effects were equivalent to a combination of NGF, BDNF, and NT-3. Analysis of receptor-specific neurotrophic activities demonstrated that PNT-1 efficiently rescued TrkA mRNA-containing sympathetic neurons and TrkB and TrkC mRNA-containing sensory neurons from the dorsal root and nodose ganglia. Finally, PNT-1 showed robust retrograde transport to DRG neurons in vivo after injection into the sciatic nerve. Radiolabeled PNT-1 accumulated in small-, medium-, and large-sized neurons. Coinjection with different unlabeled neurotrophins inhibited PNT-1 transport in distinct subpopulations of neurons of different sizes, suggesting that this molecule affects sensory neurons of different modalities. These results indicate that PNT-1 is a potent and multispecific neurotrophic factor that may be useful in the treatment of peripheral neurophathies and nerve damage.
Department of Medical Biochemistry and Biophysics, Karolinska Institute, Stockholm, Sweden.
L L
LL
Ilag
R
R
Curtis
D
D
Glass
H
H
Funakoshi
N J
NJ
Tobkes
T E
TE
Ryan
A
A
Acheson
R M
RM
Lindsay
H
H
Persson
G D
GD
Yancopoulos
D000818:Animals; D001345:Autoradiography; D001692:Biological Transport; D019208:Brain-Derived Neurotrophic Factor; D002470:Cell Survival; D002478:Cells, Cultured; D005727:Ganglia, Spinal / Q000166:cytology / Q000378:metabolism; D007457:Iodine Radioisotopes; D007553:Isotope Labeling; D008161:Lumbosacral Region / Q000294:innervation; D009414:Nerve Growth Factors / Q000235:genetics* / Q000378:metabolism* / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000235:genetics; D009474:Neurons / Q000378:metabolism*; D020933:Neurotrophin 3; D010525:Peripheral Nerves / Q000166:cytology / Q000378:metabolism*; D015202:Protein Engineering; D051381:Rats; D017475:Receptors, Nerve Growth Factor / Q000145:classification / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism*
D019208:Brain-Derived Neurotrophic Factor; D007457:Iodine Radioisotopes; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D020933:Neurotrophin 3; D017475:Receptors, Nerve Growth Factor; D011993:Recombinant Fusion Proteins; C091581:pan-neurotrophin 1