Neurotrophins are important biomarkers in Neurobiology, including stem cell development to neural lineages. BDNF and NGF are the ones being studied in most cases. However, it has been found that neurotrophins do not act independently. Many publications have described the coordinated actions of 2 or more neurotrophins, especially in development, but also in the adult.
Let’s take the gustatory system, for example. It is already known that BDNF and NT-4 have a different role in the development of this system, but how they act remains unclear. They both activate the same receptors (TrkB and p75). A recent publication by Huang & Krimm (1) has proved that, at least in taste development, roles of BNDF and NT-4 are interchangeable. Spatial and temporal differences in BDNF and NT4 expression can regulate differential gene expression in vivo and determine their specific roles during development.
If we go to peripheral nerve repair, for example, recent studies (2) indicate that BDNF, GDNF and NGF have a remarkable and selective effect on motor or sensory regeneration, by differential temporal and spatial expression. In stem-to-neural (3) differentiation in dental pulp stem cells, however, it is BDNF, NT-3 and NT-4 the ones involved in this process, as they have neurogenesis, neurotrophic or neuroprotective effects.
It is important, therefore, that studies in these areas include several neurotrophins. One alternative is to study them independently (usually by simplex ELISA), but new tools now allow simultaneous studying of all neurotrophins in the same sample, thus saving sample and time, as well as increasing the robustness of the obtained results. These tools are now available for human (NGF, BDNF, NT-3 and NT-4/5), and they will soon be ready for mouse and rat.
(2) – A comparative morphological, electrophysiological and functional analysis of axon regeneration through peripheral nerve autografts genetically modified to overexpress BDNF, CNTF, GDNF, NGF, NT3 or VEGF