The Expression of α-, β-, and γ-Synucleins in Olfactory Mucosa from Patients with and without Neurodegenerative Diseases

• Published in: Experimental neurology 1999-12, Vol.160 (2), p.515-522
• Main Authors: Duda, John E., Shah, Usman, Arnold, Steven E., Lee, Virginia M.-Y., Trojanowski, John Q.
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Alzheimer Disease - pathology; Alzheimer's disease; Biological and medical sciences; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Female; gamma-Synuclein; Humans; Immunohistochemistry; Male; Medical sciences; Middle Aged; multiple system atrophy; Multiple System Atrophy - pathology; Nerve Tissue Proteins - analysis; Neurodegenerative Diseases - pathology; Neurology; neuronal plasticity; olfactory epithelium; Olfactory Mucosa - pathology; Parkinson Disease - pathology; Parkinson's disease; Phosphoproteins - analysis; regeneration; synuclein; synuclein proteins; synucleinopathies; Synucleins
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1006/exnr.1999.7228

A family of homologous proteins known as α-, β-, and γ-synuclein are abundantly expressed in brain, especially in the presynaptic terminal of neurons. Although the precise function of these proteins remains unknown, α-synuclein has been implicated in synaptic plasticity associated with avian song learning as well as in the pathogenesis of Parkinson's disease (PD), dementia with LBs (DLB), some forms of Alzheimer's disease (AD), and multiple system atrophy (MSA). Since olfactory dysfunction is a common feature of these disorders and the olfactory receptor neurons (ORNs) of the olfactory epithelium (OE) regenerate throughout the lifespan, we used antibodies specific for α-, β-, and γ-synucleins to examine the olfactory mucosa of patients with PD, DLB, AD, MSA, and controls without a neurological disorder. Although antibodies to α- and β-synucleins detected abnormal dystrophic neurites in the OE of patients with neurodegenerative disorders, similar pathology was also seen in the OE of controls. More significantly, we show here for the first time that α-, β-, and γ-synucleins are differentially expressed in cells of the OE and respiratory epithelium and that α-synuclein is the most abundant synuclein in the olfactory mucosa, where it is prominently expressed in ORNs. Moreover, α- and γ-synucleins also were prominent in the OE basal cells, which include the progenitor cells of the ORNs in the OE. Thus, our data on synuclein expression within the OE may signify that synuclein plays a role in the regeneration and plasticity of ORNs in the adult human OE.