Recombinant human NT-3 (also known as neurotrophin-3 / nerve growth factor-2 / NGF-2/ hippocampus-derived neurotrophic factor / HDNF) protein is a member of the NGF family of neurotrophic factors (also known as neurotrophins).
NT-3 is used in the neural stem cell field promoting differentiation and survival of specific neuronal subpopulations in both the central nervous system and peripheral nervous system . This growth factor promotes the survival and differentiation of nerve cells (peripheral neurons [2,3], sensory neurons , and spinal motor neurons ) and glial cells (oligodendrocytes [6,7,8]). With its wide applications in the nervous system, NT-3 is used in human cortical organoid maturation . It also has a role in endothelial survival  and the development of the cardiovascular system [11,12].
NT-3 is part of the cysteine knot family of growth factors that share high structural homology to nerve growth factor (NGF or β-NGF), brain-derived neurotrophic factor (BDNF), neurotrophin 4 (NT-4), and neurotrophin 5 (NT-5). NT3 is structurally characterized by the presence of six conserved cysteine residues that result in each protomer forming a twisted four-stranded beta-sheet, with three intertwined disulfide bonds. Bioactive NT-3 is a non-covalently linked 27.3 kDa homodimer of two 13.6 kDa monomers . Human NT-3 cDNA encodes a 257 amino acid residue precursor protein with a signal peptide and a proprotein that is proteolytically processed to generate the 119 amino acid residue mature NT-3. The amino acid sequence of mature human NT-3 is identical to mouse, rat, and pig. NT-3 can activate two different classes of transmembrane receptors, the neurotrophin receptor p75 and the Trk tyrosine kinase receptors, binding to TrkC with the greatest affinity. In certain cell systems, NT-3 is also known to activate TrkA and TrkB kinase receptors .