| BDNF | |
|---|---|
| Full Name | Brain-Derived Neurotrophic Factor |
| Chromosome | 11p14.1 |
| Gene Type | Protein-coding gene |
| NCBI Gene ID | 627 |
| OMIM | 113505 |
| Ensembl ID | ENSG00000176697 |
| UniProt | P23560 |
| Protein Family | Neurotrophin family |
| Receptors | TrkB (NTRK2), p75NTR (TNFRSF1B) |
| Major Pathways | PI3K/Akt, MAPK/ERK, PLCγ |
| Primary Disease Links | AD, PD, HD, Depression, Rett Syndrome |
Brain-Derived Neurotrophic Factor (BDNF) is the most widely expressed neurotrophin in the mammalian brain and plays essential roles in neuronal development, survival, synaptic plasticity, and cognitive function. Discovered in the 1980s as a member of the neurotrophin family, BDNF has become one of the most studied neurotrophic factors in the context of neurodegenerative diseases, psychiatric disorders, and neural repair. [1]
BDNF is unique among neurotrophins in that its expression is highly activity-dependent, with neuronal activity, learning, exercise, and environmental enrichment all increasing BDNF transcription. This activity-dependent regulation makes BDNF a critical mediator of experience-dependent neural plasticity.
The BDNF gene is located on chromosome 11p14.1 and consists of 11 exons and 9 functional promoters, making it one of the most complexly regulated neurotrophin genes. This complex promoter architecture allows for tissue-specific, developmental stage-specific, and activity-dependent regulation.
Key exons:
BDNF is synthesized as a precursor protein (pro-BDNF, ~32 kDa) that undergoes proteolytic processing to generate the mature BDNF (~14 kDa):[2]
The balance between pro-BDNF and mature BDNF is critical for neural development and plasticity.
BDNF signals primarily through the TrkB (Tropomyosin receptor kinase B, encoded by NTRK2) receptor:[3]
Receptor structure:
TrkB isoforms:
BDNF binding to TrkB activates multiple downstream cascades:[4]
The p75 neurotrophin receptor can also bind BDNF, with context-dependent effects:
Pro-BDNF/p75NTR signaling:
Mature BDNF/p75NTR signaling:
BDNF is highly expressed in:[5]
BDNF expression is highly regulated by neuronal activity:
Upregulating factors:
Downregulating factors:
During neural development, BDNF mediates:[6]
BDNF is a critical mediator of activity-dependent synaptic changes:[7]
Long-term potentiation (LTP):
Long-term depression (LTD):
Homeostatic plasticity:
BDNF is essential for learning and memory:[5:1]
BDNF alterations in AD:[8]
Expression changes:
Pathological mechanisms:
Therapeutic strategies:
Preclinical results:
BDNF supports dopaminergic neurons:[10]
Dopaminergic protection:
Therapeutic development:
BDNF is crucial for striatal neuron function:[11]
Dysregulation in HD:
Therapeutic potential:
BDNF is a key mediator of antidepressant efficacy:[12]
Clinical findings:
Mechanisms:
Rett Syndrome:
Epilepsy:
| Approach | Advantages | Limitations | Status |
|---|---|---|---|
| Recombinant BDNF | Well-characterized | BBB penetration | Preclinical |
| AAV-BDNF | Long-term expression | Immune response | Clinical trials |
| TrkB agonists | Oral delivery | Specificity | Preclinical |
| Exercise | Natural, safe | Variable | Proven |
| Antidepressants | FDA-approved | Indirect | Approved |
Small molecule TrkB agonists being developed:
AAV-mediated BDNF delivery:[4:1]
Complete BDNF knockout is embryonic lethal, demonstrating the essential role during development. Conditional knockout models have provided crucial insights:
** forebrain-specific knockout:**
Neuron-specific knockout:
Transgenic overexpression:
Viral-mediated overexpression:
| Compound | Mechanism | Stage | Notes |
|---|---|---|---|
| 7,8-DHF | TrkB agonist | Preclinical | First-generation |
| Nor-BDNF | BDNF derivative | Research | More stable |
| R13 | TrkB-selective | Preclinical | Oral bioavailability |
| ANA-12 | TrkB antagonist | Research | Used to study BDNF role |
BDNF mediates the effects of:
The functional Val66Met polymorphism (rs6265) affects:
Binder DK, Scharfman HE. Brain-derived neurotrophic factor. Growth Factors. 2004. ↩︎
Cowley S, et al. Activation of MAP kinase by BDNF. Cell. 1994. ↩︎
Huang EJ, Reichardt LF. Trk receptors: roles in neuronal signal transduction. Annu Rev Neurosci. 2003. ↩︎
Gomes JR, et al. TrkB signaling in dendrites and synaptic plasticity. J Neurochem. 2012. ↩︎ ↩︎
Kowianski P, et al. BDNF: a key factor in synaptic plasticity and memory. J Neural Transm. 2018. ↩︎ ↩︎
Carroll P, et al. BDNF and activity-dependent neuronal survival. Neurochem Res. 1995. ↩︎
Pizzorusso T, et al. BDNF and synaptic plasticity in the adult brain. Learn Mem. 2002. ↩︎
Allen SJ, et al. BDNF: a key therapeutic target for Alzheimer's disease. Nat Rev Neurol. 2013. ↩︎
Liu Y, et al. AAV-mediated BDNF expression improves cognitive deficits in Alzheimer's disease models. Mol Neurobiol. 2015. ↩︎
Levy MJ, et al. AAV-BDNF gene therapy for Parkinson's disease. Mol Ther. 2018. ↩︎
Colucci-D'Amato L, et al. BDNF/TrkB signaling in Huntington's disease. J Mol Neurosci. 2008. ↩︎
Tapia-Arancibia L, et al. BDNF signaling in neuroinflammation and neurodegenerative diseases. J Neurochem. 2011. ↩︎