Cerebroprotein Hydrolysate

The article examines the potential role of brain mechanical damage as a trigger for the development of neurodegenerative changes. Attention is paid to dysfunction of the neurovascular unit, and disruption of the functional and compensatory capabilities of blood flow. The importance of microhemorrhages that occur in the acute period of injury and the formation of first focal and then diffuse neuroinflammation is emphasized. The importance of mitochondrial dysfunction was separately determined as a significant factor in increasing the risk of developing Alzheimer's disease (AD) in patients after traumatic brain injury (TBI). In TBI, there is a decrease in the expression of tight junction (TC) proteins of endothelial cells, such as occludin, claudin, JP, which leads to increased permeability of the blood-brain barrier. TBI, provoking endothelial dysfunction, contributes to the development of metabolic disorders of β-amyloid and tau protein, which in turn leads to worsening vascular damage, resulting in a vicious circle that can ultimately lead to the development of AD and dementia. Age-related changes in cerebral arteries, which impair perivascular transport of interstitial fluid, are currently considered as an important part of the «amyloid cascade», especially against the background of genetically mediated disorders of glial membranes associated with defective aquaporin-4 (encoded by the APOE4). Studies in animal models of TBI have revealed an increase in tau protein immunoreactivity and its phosphorylation, which correlates with the severity of injury. A comprehensive analysis of research results shows that the cascade of reactions triggered by TBI includes all the main elements of the pathogenesis of AD: disorders of energy metabolism, microcirculation and clearance of cerebral metabolic products. This leads to a disruption in the metabolism of amyloid protein and its accumulation in brain tissue with the subsequent development of tauopathy. Cerebrolysin, by modulating the permeability of the blood-brain barrier, blocks the development of neuroinflammation, reduces the accumulation of pathological forms of proteins and may be slow down the progression of neurodegeneration.

Neurotrophic activity constitutes a crucial factor in the recovery from neurological injuries and is impaired in neurodegenerative disorders. Preclinical studies of neurotrophic factors to improve outcome of neurodegenerative diseases have yielded promising results. However, due to the complexity of these therapies, the clinical translation of this approach was so far not successful and more feasible treatments with neurotrophic activity may be promising alternatives. Therefore, highly sensitive and robust assays for compound screening are required.

Nerve growth factor is known to induce Neurofilament-L (NF-L) expression in a rat pheochromocytoma cell line (PC12 cells) during early neuronal differentiation. We generated and characterized an enhanced green fluorescent protein (EGFP)-NF-L reporter PC12 cell line for the development of a cell-based assay (designated Neurofilament-L Bioassay) that allows straightforward quantification of early neuronal differentiation based on NF-L expression.

Using Cerebrolysin® as a role model for a pharmacological compound that stimulates neurotrophic activity in the central nervous system, the Neurofilament-L Bioassay was proved to be a robust, specific, and reproducible method.

It was already shown that NF-L expression correlates with neurite outgrowth in PC12 cells. Currently, quantification of neurite outgrowth is the most commonly used method to evaluate neuronal differentiation in PC12 cells, an approach that is time-consuming and of high variability.

This work describes the development of an EGFP-NF-L reporter PC12 cell-based assay as a robust and reproducible tool for "high throughput" compound screening for neurotrophic activity.