Nerve growth factor is a neurotrophic peptide hormone involved in neuronal survival, sensory nerve maintenance, synaptic plasticity, immune communication, and nervous system development. NGF functions as one of the most important growth factors for survival and maintenance of sympathetic neurons and sensory neurons throughout the peripheral nervous system.
The hormone supports neuronal differentiation, axonal growth, synaptic organization, and repair-related signaling after neural injury. NGF also influences immune-cell activity, inflammatory communication, pain signaling pathways, and neuroimmune interactions. Through these actions, it coordinates communication between nervous tissue, immune systems, and regenerative cellular pathways.
NGF is produced by neurons, glial cells, immune cells, epithelial tissues, fibroblasts, smooth muscle cells, and connective tissue structures. Production occurs both during embryonic development and throughout adulthood where ongoing neuronal maintenance and repair signaling are required.
The hormone is synthesized as a precursor protein that undergoes enzymatic processing into mature biologically active NGF. Local tissue production allows highly targeted paracrine signaling between neurons and supporting cellular environments. Peripheral tissues can also release NGF during injury and inflammatory activation.
NGF production is regulated by inflammatory cytokines, tissue injury, oxidative stress, neuronal activity, immune signaling pathways, and developmental transcription programs. Inflammatory mediators and cellular stress can strongly increase NGF expression during repair-associated responses.
NGF acts primarily through TrkA receptor tyrosine kinases and p75 neurotrophin receptors located on neurons and additional cell populations. Activation stimulates MAP kinase pathways, PI3K-AKT signaling, calcium-regulated cascades, and survival-associated transcription systems. Receptor internalization and retrograde axonal transport help coordinate long-distance neuronal signaling. Through these integrated neurotrophic signaling systems, NGF regulates neuronal survival, sensory maintenance, tissue repair communication, and neuroimmune coordination.
NGF promotes survival and plasticity of select neurons and coordinates trophic repair signals.
