{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nNeurturin (NRTN), a member of the glial cell line‐derived neurotrophic factor family, plays a key role in synaptic development and neuromuscular junction formation. Experiments in Xenopus nerve–muscle co‐cultures revealed that NRTN, paralleling the effects of GDNF, enhances neurite outgrowth, promotes synaptic vesicle clustering, and increases neurotransmitter release through both presynaptic and postsynaptic mechanisms (1). In addition, studies on developing human teeth and hippocampal regions have identified distinct, albeit weak, NRTN mRNA expression patterns that suggest roles in morphogenetic events and the establishment of neural innervation (2, 3).\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its classical neurotrophic functions, NRTN is produced by cells of the immune system—including T cells, B cells, and monocytes—where it participates in paracrine communication that can modulate cytokine levels, such as reducing TNF protein release. In neuronal models, NRTN signaling via its receptor complex (engaging primarily GFRα2) influences gene regulatory networks by differentially modulating miRNA precursor expression and driving neurite outgrowth through a cAMP–PKA-dependent, biphasic ERK1/2 activation cascade. Notably, alternative splice variants of GFRα2 affect these outcomes, while NRTN expression has also been linked to peripheral tissue regulation such as hair follicle cycling and even the development of the enteric nervous system implicated in Hirschsprung disease (4, 5, 6, 7, 8, 9).\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn models of cellular stress, NRTN confers neuroprotective effects by mitigating both neuronal and glial damage. In pathological settings, aberrant or increased NRTN signals are associated with disease progression; for example, elevated NRTN levels in pancreatic cancer are linked to enhanced tumor invasiveness, and in hepatocellular carcinoma, the TANGO1/NRTN axis has been shown to promote proliferation, inhibit apoptosis, and trigger epithelial–mesenchymal transition through the activation of the PI3K/AKT/mTOR cascade. Structural studies—including both crystal structure analysis of the NRTN–GFRα2 complex and cryo-electron microscopy of the complete extracellular RET signaling assembly—have provided crucial insights into the molecular bases of its receptor interactions and activation mechanisms. Furthermore, the successful development of scalable methods to produce biologically active recombinant NRTN reinforces its therapeutic potential in neurodegenerative diseases such as Parkinson's disease, and assessments of its expression in the human cochlea suggest a role in auditory system maintenance (10, 11, 12, 13, 14, 15, 16).\n"}, {"type": "rg", "children": []}]}]}