Neurotrophic factors

About Neurotrophic Factors:

A family of biomolecules; Neurotrophic Factors (NTFS) consist mainly of small proteins and peptides, which include Nerve Growth Factor (NGF), glial cell line–derived neurotrophic factor (GDNF) family ligands, brain-derived neurotrophic factor (BNDF), and neuropoietic cytokines; which are essential to the differentiation, survival, and growth of neurons in all stages of development. Neurotrophic Factors promote the development and initial growth of neurons in both nervous systems; the central nervous system and the peripheral nervous systems. They have been found able to regenerate and repair neurons that were damaged or faulty both in lab experiments (test tube models) as well as animals.
As well as regenerative effects, and helping with growth, Neurotrophic Factors promote survival of neurons, induce synaptic plasticity, and help to regulate and modulate the creation of the long-term memory. They have also been linked to having a potentially strong role in the treatment of neurodegenerative diseases such as MS.
They also act as survival factors, and ensure that there is a constant equilibrium between the amount of surviving neurons and the appropriate target innervation. They also serve a vital role in regulating and making decisions around cell fate, dendrite pruning, the patterning of innervation, as well as axon growth and the creation of the proteins vital for continued normal function of ion channels and neurotransmitters, as well as other neuronal function.

Neurotrophic Factors structure
Each Neurotrophic Factor has a slightly different structure, and can be specifically researched; for example, the three-dimensional structure of NGF (Nerve Growth Factor) has been studied and documented, and there is ongoing research into the crystal structures of BNDF (Brain-derived Neurotrophic Factor), as well as others we haven’t mentioned here; NT-4 (Neurotrophin-4) and NT-3 (Neurotrophin-3).
Another example of Neurotrophic structure can be explored in NT-3; which has a unique receptor (TrkC). NT-3 is therefore unique amongst Neurotrophic Factors, despite sharing similar properties, and still being considered important to neuronal survival.

Neurotrophic Factors location and functions
As expected, Neurotrophic Factors are found throughout both nervous systems, and are therefore in all areas of the human body. NT-3 for example is found specifically in the intestinal epithelium, spleen, and thymus; but scientists have thus far been unable to determine its function.
One Neurotrophic Factor that there is more known about is Brain-derived Neurotrophic Factor (BDNF). This is similar in structure to NGF, NT-3 and NT-4 / NT-5, and shares the TrkB receptor with NT-4. Scientists know this to promote thymocyte survival, as observed in rodent’s thymus. Moreover, BDHF promotes survival of dorsal root ganglion neurons, and even when it has been bound to truncated forms of TrkB, it shows strong developmental roles. It is therefore essential to survival and neuron development; so much so that when removed from rodents in scientific studies, the mice did not live longer than 3 weeks.
One final function of BDNF is important regulatory roles in the hippocampus; the part of the brain responsible for temporal location, and our navigation. Low BDNF and other Neurotrophic Factor levels have also been seen in patients with untreated depression, but this is controversial, and still under dispute.