Neuronal Transcytosis of WGA Conjugated Protein

Abstract

Neuronal transcytosis was observed at the stage when no neurotransmitter was released after the injection of wheat germ agglutinin-conjugated horseradish peroxidase (WGA-HRP; WGA = 22 kDa, HRP = 40 kDa) into the vagus nerve. The co-injection of Rab3A-siRNA with WGA-HRP into the vagus nerve was performed to further examine this phenomenon. This co-injection resulted in the transcytosis of WGA-HRP, both of the passing type, by which it crossed the synapses, and of the secretion type followed by endocytosis of postsynaptic membranes. These findings raised the possibility in vivo that WGA plays an important role in the transcytosis of protein. Therefore, WGA may be a valuable tool for therapeutic drug targeting via transcytosis. The ability of WGA-conjugated Amyloid ß (WGA-Aß) to decrease amyloid deposits in Alzheimer’s disease was investigated. The conjugation of WGA to amyloid-ß (1-40) (Aß; 5 kDa) was confirmed. WGA-Aß was then shown to move to terminals by axonal flow in vivo as well as WGA-HRP. WGA-Aß was also observed in the nodose ganglion cells and terminals after injections of fluorescent Aß (FAß) into the vagus nerve and fluorescent WGA (FWGA) into the common carotid artery. These studies suggested that WGA-Aß could be localized to solitary neurons via transcytosis.