Expression of peripherin in the brain of macaques (Macaca mulatta and Macaca fascicularis) occurs in astrocytes rather than neurones and is associated with encephalitis

Peripherin is a member of the type III intermediate filament family, expressed in neurones of the peripheral nervous system of many species and in a discrete subpopulation of neurones of the central nervous system (CNS) during early development in rodents. Previous studies on rats have shown that peripherin immunoreactivity increased significantly in cell bodies of spinal motor neurones following axonal injury. Our study examined the expression of peripherin in the cerebrum of normal macaques (Macaca mulatta and Macaca fascicularis) and those with encephalitis of viral (simian immunodeficiency virus and simian virus 40) or autoimmune (experimental allergic encephalomyelitis) aetiology. Immunohistochemistry, immunoelectronmicroscopy, immunofluorescence and confocal microscopy were performed on tissue sections using antibodies against cell-specific markers and peripherin. Peripherin-positive cells were absent in the cerebrum of normal macaques of all ages examined, whereas animals with encephalitis had peripherin-positive cells associated with inflammatory infiltrates. Further evaluation revealed that these peripherin-positive cells were not neurones, but were predominantly astrocytes expressing glial fibrillary acidic protein. Our study suggests that peripherin is not neurone-specific in the CNS of macaques; peripherin is expressed in astrocytes of animals with encephalitis.     

Triton-soluble phosphovariants of the heavy neurofilament subunit in developing and mature mouse central nervous system

The low abundance of soluble neurofilament (NF) subunits in mature axons has suggested that newly synthesized NF proteins rapidly assemble into highly stable polymers and associate with the Triton X-100–insoluble cytoskeleton. The dynamic nature of these subunit associations in vivo remains unresolved, and the applicability of this assembly model to NFs in other neuronal compartments or to developing neurons is unknown. Here, we report that a unique pool of Triton X-100–soluble, extensively phosphorylated, high molecular weight NF subunits (NF-H, or H-200) are abundantly expressed in the mouse CNS during early postnatal development and persist in the perikaryal compartment of some mature neurons. Triton-soluble H-200 subunits appeared at postnatal day 14 (P14) and remained high through P60, beyond which the percentage declined to marginal levels by P120. Medium and low molecular weight NF (NF-M and NF-L, respectively) were at all times only detectable within the cytoskeleton. Comparison of soluble and cytoskeleton-associated H-200 immunoreactivity indicated that certain phosphorylation-dependent epitopes were confined to the cytoskeleton. Pulse-chase radiolabeling analyses in optic pathway demonstrated that some Triton-soluble NF-H subunits are extensively phosphorylated within retinal perikarya before they are incorporated into Triton-insoluble structures. These findings indicate that the assembly behaviors of NF-H differ substantially from those of NF-M and NF-L, and that the interaction of NF-H with NFs may be more dynamic than is generally recognized, especially during brain development and within specific compartments of mature neurons. J. Neurosci. Res. 48:515–523, 1997. © 1997 Wiley-Liss Inc.     

Synaptophysin and chromogranin A immunoreactivities of Lewy bodies in Parkinson's disease brains

Lewy bodies commonly observed in brains with Parkinson's disease (PD) histochemically contain both protein and lipid as chemical components. Ultrastructurally, they are composed of filamentous, vesicular and granular structures. We investigated PD brains with light and electron microscopic immunohistochemistry using antibodies against two marker proteins for neuronal secretory vesicles, synaptophysin and chromogranin A. Both antibodies immunolabeled the peripheral zones and occasionally central cores of Lewy bodies of the classical and intraneuritic types. In addition, the diffuse immunolaballing was observed in Lewy bodies of the cortical type. Furthermore, the ultrastructural immuno-decoration was found mainly in the vesicular structures, and also in the filamentous and granular structures of Lewy bodies. Immuno-blot analysis of each antibody showed no difference between PD and normal control brains. The present observations suggest that vesicular profiles of Lewy bodies represent presynaptic and dense core secretory vesicles, and therefore that the lipid elements of Lewy bodies are derived from membrane lipids of these vesicles.     

Microtubule-associated protein 5 is a component of Lewy bodies and Lewy neurites in the brainstem and forebrain regions affected in Parkinson's disease

Ubiquitin-positive Lewy neurites and Lewy bodies are found in idiopathic Parkinson's disease (PD) and diffuse Lewy body disease (DLBD). We found that, in three patients with PD and one with DLBD, microtubule-associated protein 5 (MAP5) immunostaining was consistently present in both Lewy neurites and Lewy bodies throughout the brainstem and forebrain regions affected in the disease. In contrast, other cytoskeletal markers (neurofilaments and MAP2) could be demonstrated in only a small fraction of Lewy bodies and neurites. Confocal microscopy demonstrated that MAP5 immunolabeling was located around the perimeter of the ubiquitin-positive labeling which occupied the central region of the neurite and Lewy body, with some overlap between MAP5 and ubiquitin staining. In contrast, in those Lewy bodies and neurites immunopositive for phosphorylated and non-phosphorylated neurofilament proteins, the neurofilament labeling was quite peripheral to the ubiquitin staining, with little or no overlap. Our results suggest MAP5 is more closely associated with the ubiquitinated proteins of Lewy bodies and neurites than other cytoskeletal proteins. Received: 3 July 1995 / Revised, accepted: 8 September 1995     

Light subunit of neurofilament triplet protein in the cerebrospinal fluid after subthalamic nucleus stimulation for Parkinson's disease

Constantinescu R, Holmberg B, Rosengren L, Corneliusson O, Johnels B, Zetterberg H. Light subunit of neurofilament triplet protein in the cerebrospinal fluid after subthalamic nucleus stimulation for Parkinson’s disease.
Acta Neurol Scand: 2011: 124: 206–210.
© 2010 John Wiley & Sons A/S. Objectives – Cerebrospinal fluid (CSF) levels of neurofilament triplet protein (NFL), a non‐specific marker of neuronal damage, are normal in Parkinson’s disease (PD) but increased after brain trauma and in several neurological disorders. Using longitudinal CSF‐NFL measurements as an indicator of neuronal damage, this study investigated the impact of deep brain stimulation (DBS) of the subthalamic nucleus (STN) on the brain, directly following the surgical intervention and in chronically treated patients with PD. Materials and methods – CSF‐NFL levels were measured consecutively in eight patients with PD before and after STN‐DBS treatment. Results – CSF‐NFL levels were normal prior to STN‐DBS and increased sharply during the first 2 weeks post‐operatively, but normalized after 12 months or more. Conclusion – The STN‐DBS procedure leads to an acute but limited neuronal damage, as expected. However, normal CSF‐NFL levels at 12 months post‐operatively and beyond suggest the absence of any long‐term neuronal damage caused by long‐term STN‐DBS stimulation.     

Amyloid β protein (Aβ) deposition in dementia with Lewy bodies: predominance of Aβ42(43) and paucity of Aβ40 compared with sporadic Alzheimer's disease

Amyloid β protein (Aβ) deposition was investigated by quantitative immunohistochemistry in 13 cases of dementia with Lewy bodies (DLB) and compared with that in a series of age, gender and ApoE genotype matched cases of Alzheimer's disease (AD). In DLB the predominant Aβ peptide species deposited was Aβ₄₂₍₄₃₎ and this was similar in amount to that in AD. By contrast, Aβ₄₀ deposition was sparse in DLB and was lower than that in AD as was the total Aβ (Aβ₄₀+Aβ₄₂₍₄₃₎ ) deposition. These data reinforce the viewpoint that in all disorders in which Aβ deposition is characteristic, the initial and predominant peptide species deposited is the longer form, Aβ₄₂₍₄₃₎ . The density of Lewy bodies (LB) in DLB was unrelated to the extent of Aβ deposition, although those cases possessing one or more copies of the apolipoprotein E E4 allele had a higher LB density than those without an E4 allele. This suggests that the apolipoprotein E E4 isoform might facilitate, though not necessarily trigger, the formation of LB in susceptible individuals.