Disease relevance of Nefh

• Of the ganglion cells, preferential labeling was seen in small-sized ganglion cells, whereas a monoclonal antibody to the 150 and 200 kDa neurofilament triplet (NFT) components labeled the large-sized ganglion cells [1].
• Cultured sympathetic neurons were infected with recombinant adenovirus containing a construct encoding a fusion protein combining green fluorescent protein (GFP) with the heavy neurofilament protein subunit (NFH) [2].
• Alterations of a 200 kDa neurofilament in the rat hippocampus after forebrain ischemia [3].
• We have shown previously that subcytotoxic concentrations of MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) inhibit axon outgrowth and are associated with increased neurofilament heavy chain (NF-H) phosphorylation in differentiating mouse N2a neuroblastoma cells while higher doses (> 100 microM) cause cell death [4].
• The present results indicate that both the 68- and the 200-kDa neurofilament genes are constitutively active in uninduced F9 teratocarcinoma cells [5].

Psychiatry related information on Nefh

• Postnatal developmental profiles of filamentous actin and of 200 kDa neurofilament polypeptide in the visual cortex of light- and dark-reared rats and their relationship to critical period plasticity [6].
• Previous studies from our laboratory suggest that Alzheimer's disease sera contain a repertoire of antibodies to the heavy neurofilament subunit (NF-H) and that a subpopulation of these antibodies bind specifically to epitopes highly enriched in NF-H isolated from the purely cholinergic electromotor neurons of Torpedo [7].
• The results indicate that morphine addiction is associated with an aberrant hyperphophorylation of NF-H in the rat brain [8].
• Production of such Abs in EAD rats by prolonged immunization with Torpedo cholinergic NF-H results in the accumulation of IgG in the septum and hippocampus of the immunized rats and in memory deficits [9].

High impact information on Nefh

• Most phosphorylation occurs in the lys-ser-pro (KSP) repeats in the C-terminal tail domains of NF-H and NF-M [10].
• The stable NF-H-expressing cell lines can therefore be used to study these putative neurofilament kinases in vitro and in vivo [11].
• These results indicate that phosphorylation of NF-H, but not NF-M, on the KSP sequence is due to protein kinases, which are not present in fibroblasts and are presumably NF-H specific [11].
• SDS-PAGE and immunoblotting analyses show that untreated and NGF-treated PC12 cells also contain relatively minor amounts of the 68, 150, and 200 kDa neurofilament triplet (NFT) proteins [12].
• Small- and large-diameter sensory neurons exhibited elevated levels of NF-H protein accumulation and phosphorylation in the DRG of untreated diabetic rats, levels that were ameliorated by NT-3 [13].

Biological context of Nefh

• The identity of the cDNAs was established by comparison of the predicted amino acid sequence with the known partial amino acid sequence of porcine NF-H [14].
• Cellular expression of the microglia/macrophage antigen ectodysplasin A (ED1) was reduced in nude rats as compared to heterozygotes, but no difference was observed in expression levels of 5-hydroxytryptamine, the 200-kDa neurofilament, or glial fibrillary acidic protein [15].
• By transient transfection assays, we have shown that NF-H can only be extensively phosphorylated in the presence of both Cdk5 and p35 [16].
• Examination of slow axonal transport revealed that the transport rate for NF-M was slightly faster than that for NF-H in young rats, but slightly slower in aged rats [17].
• Later the intensity of the immunoreactivity to RT97 (a monoclonal antibody to the phosphorylated 200 kDa neurofilament subunit) as well as the cell size (cross-sectional area at the nuclear level) were measured in the dye-injected neurons [18].

Anatomical context of Nefh

• The developmentally regulated intracellular intermediate filament protein neurofilament (NF), composed of the light (NF-L), medium (NF-M) and high (NF-H) molecular weight isoforms, is expressed abundantly in nerve cells but its significance in nerve cell survival in stress situations in the brain is unknown [19].
• Two-dimensional gel analysis and immunoblotting of total proteins from adult rat dorsal root ganglion verified mAb specificity in situ, and showed that differentially phosphorylated isoforms of NF-M and NF-H occur in vivo [20].
• Alteration in the concentration of a 200 kDa neurofilament (NF200) in the rat hippocampus after forebrain ischemia and its relationship to hippocampal neuronal death were studied with an anti-200 kDa neurofilament antibody, using immunohistochemical and immunoblotting techniques [3].
• On the role of the 200-kDa neurofilament protein at the developing neuromuscular junction [21].
• A pronounced decrease in phosphorylation-related immunoreactivity of NF-H occurred as early as 1 day after the injection in the amygdala/pyriform cortex, hippocampus, striatum, and dorsal cerebral cortex [22].

Associations of Nefh with chemical compounds

• This suggests that glutamate causes increased NF-H phosphorylation at least in part by activation of stress activated protein kinases [23].
• Phosphorylation of NF-H by the cdc2-like activity was not affected by 3 microM olomoucine but was inhibited by 10 microM of this kinase inhibitor [24].
• In the control nerve, 15-25% of high-molecular-mass NF subunit (NF-H) was recovered in the 1% Triton-soluble fraction when fractionated in the presence of phosphatase inhibitors [25].
• In this study, neurofilament (NF) proteins were examined following intraperitoneal injection of kainic acid, and special reference was given to temporal changes in quantity and quality of the NF light (NF-L) and heavy (NF-H) subunits [22].
• No alterations of the light subunit of neurofilament proteins occurred, suggesting that KA has a preferential effect on NF-H phosphorylation [26].

Enzymatic interactions of Nefh

• We conclude that cdk-5 and GSK-3 phosphorylate different residues or sets of residues within NF-H sidearm in cells [27].

Regulatory relationships of Nefh

• Rat olfactory neurons express a 200 kDa neurofilament [28].

Other interactions of Nefh

• In the present study, the expression of VRL1 by A- or C-fiber sensory neurons in rats was investigated by using a VRL1 and 200 kDa neurofilament (NF200, an A-fiber marker) double immunohistochemical staining method [29].
• The identities of these two phosphoproteins as microtubule-associated protein-2 (MAP-2) and the 200 kDa neurofilament subunit (NF), respectively, were established using immunoprecipitation techniques with monoclonal antibodies [30].
• Evaluation of phosphorylated 200-kDa neurofilament immunoreactivity revealed a decreased immune reaction area in the CA1 subfield of 6-month-old SHR compared to age-matched WKY rats and no changes in the expression and localization of the dendritic marker microtubule associated protein (MAP)-2 [31].

Analytical, diagnostic and therapeutic context of Nefh

• Sequence analysis shows that rat NF-H has an overall homology of 72 and 88% with human and mouse NF-H, respectively [11].
• Furthermore, the 200 kDa neurofilament protein (NF-H) was persistently detected in Western blots during periods of active regeneration, a finding that contrasts with the late appearance of the NF-H during the developmental growth of retinal axons [32].
• Using enzyme-linked immunosorbent assays the concentrations of 68- and 200-kDa neurofilament polypeptides were shown to be reduced in all brain regions studied [33].
• Axonal elements, as revealed by neurofilament (NF-H/M) immunohistochemistry, in the corticothalamic transition zone displayed pathomorphological changes, such as axonal bulbs and swellings, already 4 h after insult [34].
• Northern blot analysis of severed nerve detected NF-L and NF-M, but not NF-H [35].

References