Abstract
Cardiotrophin-1 (CT-1) is a potent neurotrophic factor for motoneurons but its clinical use in motor neuron diseases is precluded by side effects on the heart and liver. We explored the possibility of targeting CT-1 to neurons by coupling with the tetanus toxin fragment TTC. Genetic fusion proteins between CT-1 or GFP and TTC were produced in Escherichia coli and assayed in vitro. In contrast to uncoupled CT-1 or GFP, TTC-coupled proteins bound with high affinity to cerebral neurons and spinal cord motoneurons and were rapidly internalized. Glia, hepatocytes, or cardiomyocytes did not show detectable binding or uptake of TTC-coupled proteins. Similar to CT-1, TTC-coupled CT-1 induced IL-6 secretion by KB cells, activated Reg-2 gene expression, and promoted motoneuron survival in a dose-dependent manner. In vivo studies will test whether TTC-coupled CT-1 might be targeted to degenerating spinal cord or brain-stem motoneurons and migrate trans-synaptically to cortical motoneurons, which are also affected in amyotrophic lateral sclerosis.
Copyright 2001 Academic Press.
Publication types
-
Research Support, Non-U.S. Gov't
MeSH terms
-
Animals
-
Brain / cytology
-
Brain / drug effects
-
Brain / metabolism
-
Cell Survival / drug effects
-
Cell Survival / physiology
-
Cells, Cultured / cytology
-
Cells, Cultured / drug effects*
-
Cells, Cultured / metabolism
-
Cytokines / genetics
-
Cytokines / pharmacology*
-
Dose-Response Relationship, Drug
-
Escherichia coli / genetics
-
Fetus
-
Gene Expression / drug effects
-
Gene Expression / physiology
-
Green Fluorescent Proteins
-
Heart / drug effects
-
Heart / physiology
-
Hepatocytes / cytology
-
Hepatocytes / drug effects
-
Hepatocytes / metabolism
-
Humans
-
Interleukin-6 / genetics
-
Interleukin-6 / metabolism
-
Luminescent Proteins / analysis
-
Luminescent Proteins / genetics
-
Mice
-
Motor Neuron Disease / drug therapy*
-
Motor Neuron Disease / metabolism
-
Motor Neuron Disease / physiopathology
-
Motor Neurons / cytology
-
Motor Neurons / drug effects*
-
Motor Neurons / metabolism
-
Nerve Growth Factors / genetics
-
Nerve Growth Factors / pharmacology*
-
Peptide Fragments / genetics
-
Peptide Fragments / pharmacology*
-
Protein Engineering / methods
-
Recombinant Fusion Proteins / chemical synthesis
-
Recombinant Fusion Proteins / genetics
-
Recombinant Fusion Proteins / pharmacology*
-
Signal Transduction / drug effects
-
Signal Transduction / genetics
-
Spinal Cord / cytology
-
Spinal Cord / drug effects
-
Spinal Cord / metabolism
-
Tetanus Toxin / genetics
-
Tetanus Toxin / pharmacology*
Substances
-
Cytokines
-
Interleukin-6
-
Luminescent Proteins
-
Nerve Growth Factors
-
Peptide Fragments
-
Recombinant Fusion Proteins
-
Tetanus Toxin
-
tetanus toxin fragment C
-
Green Fluorescent Proteins
-
cardiotrophin 1