Neurotrophic Factor
A class of proteins supporting neuronal survival, growth, and function. Major families include neurotrophins (NGF, BDNF), GDNF family ligands, and neuropoietic cytokines. Reduced neurotrophic factor levels are associated with neurodegenerative diseases. Some research peptides are investigated for neurotrophic effects.
Technical Context
Neurotrophic factor families: (1) Neurotrophins (NGF, BDNF, NT-3, NT-4/5) — act through Trk receptor tyrosine kinases (TrkA for NGF, TrkB for BDNF/NT-4, TrkC for NT-3) and p75NTR (pan-neurotrophin receptor, mediating both survival and apoptotic signalling depending on context). (2) GDNF family ligands (GDNF, neurturin, artemin, persephin) — act through GFRα co-receptors and RET receptor tyrosine kinase. (3) Neurokines/neuropoietic cytokines (CNTF, LIF, IL-6) — act through gp130 signalling. Therapeutic delivery challenge: neurotrophic factors are proteins that do not cross the BBB, limiting systemic administration. Delivery strategies: intrathecal/intracerebroventricular injection, gene therapy (viral vectors encoding neurotrophic factors), cell-based therapy (implanting cells engineered to secrete neurotrophic factors), and small molecule/peptide mimetics that cross the BBB and activate neurotrophin receptors.