Brain-derived neurotrophic factor (BDNF) is a 13.6 kDa (or 27.2 kDa dimer) member of the neurotrophin family. BDNF has identical amino acid sequence in human, mouse, and pig with full cross-reactivities. BDNF is important in development and maintenance of neuronal populations within the central nervous system or cells directly associated with it. BDNF has been shown to enhance the survival and differentiation of several classes of neurons in vitro, including neural crest and placode-derived sensory neurons, dopaminergic neurons in the substantia nigra, basal forebrain cholinergic neurons, hippocampal neurons, and retinal ganglial cells.
Ciliary neurotrophic factor was first identified as a survival factor for neurons from the ciliary ganglion of chicken embryos. Most of its known actions are restricted to cells of the nervous system, including motor neurons, sympathetic ganglion neurons, sensory neurons, hippocampal neurons, and medial septal neurons. CNTF also prevents degeneration of motor axons after axotomy and promotes astrocyte differentiation and oligodendrocyte survival and maturation. Outside the nervous system, CNTF maintains embryonic stem cells in an undifferentiated, pluripotent state. CNTF is structurally related to leukemia inhibitory factor (LIF), interleukin-6 (IL-6), interleukin-11 (IL-11) and oncostatin M (OSM). CNTF exerts its actions through the activation of the high-affinity CTNF receptor complex, which contains the ligand-binding α-subunit (CNTF Rα) and two signal transducing β-subunits (LIF Rβ and gp130). CNTF is localized in the cell nucleus subsequent to receptor binding. Human and rat ciliary neurotrophic factor share ~83% sequence homology and show cross-reactivity in bioactivity.
Ciliary neurotrophic factor was first identified as a survival factor for neurons from the ciliary ganglion of chicken embryos. Most of its known actions are restricted to cells of the nervous system, including motor neurons, sympathetic ganglion neurons, sensory neurons, hippocampal neurons, and medial septal neurons. CNTF also prevents degeneration of motor axons after axotomy and promotes astrocyte differentiation and oligodendrocyte survival and maturation. Outside the nervous system, CNTF maintains embryonic stem cells in an undifferentiated, pluripotent state. CNTF is structurally related to leukemia inhibitory factor (LIF), interleukin-6 (IL-6), interleukin-11 (IL-11) and oncostatin M (OSM). CNTF exerts its actions through the activation of the high-affinity CTNF receptor complex, which contains the ligand-binding α-subunit (CNTF Rα) and two signal transducing β-subunits (LIF Rβ and gp130). The LIF Rβ subunit is also shared by receptors for LIF and OSM. The gp130 subunit is also shared by receptors for LIF, OSM, IL-6, and IL-11. CNTF is localized in the cell nucleus subsequent to receptor binding. Human and rat CNTF share ~83% sequence homology and show cross-reactivity in bioactivity.
